Author: "Sismologie (IPGS)" / Topic: seismology - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Sismologie (IPGS)"' showing total 68 results

Start Over Author "Sismologie (IPGS)" Topic seismology

68 results on '"Sismologie (IPGS)"'

1. Impact of 3-D Earth structure on W-phase CMT parameters

Author: Catalina Morales-Yáñez, Zacharie Duputel, Luis Rivera, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Wave propagation, Earthquake source observations, Earth structure, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), Physics::Geophysics, Geochemistry and Petrology, Inverse theory, Seismogram, Spherical Earth, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Centroid, Small amplitude, Geophysics, 13. Climate action, engineering, Structure of the Earth, Surface waves and free oscillations, Seismology, Geology
Abstract: SUMMARYWe investigate the impact of unmodelled 3-D structural heterogeneity on inverted W-phase source parameters. We generate a large data set of synthetic seismograms accounting for the Earths 3-D structure for 250 earthquakes globally distributed. The W-phase algorithm is then used to invert for earthquake CMT parameters, assuming a spherical Earth model. The impact of lateral heterogeneity is assessed by comparing inverted source parameters with those used to compute the 3-D synthetics. Results show that the 3-D structure mainly affects centroid location while the effect on the other source parameters remains small. Centroid mislocations present clear geographical patterns. In particular, W-phase solutions for earthquakes in South America are on average biased 17 km to the east of the actual centroid locations. This effect is significantly reduced using an azimuthally well balanced distribution of seismological stations. Source parameters are generally more impacted by mantle heterogeneity while the scalar moment of shallow earthquakes seems to be mainly impacted by the crustal structure. Shallow earthquakes present a variability of Mrθ and Mrϕ moment tensor elements, resulting both from the small amplitude and a larger uncertainty of the associated Green’s functions.
Published: 2020
Full Text: View/download PDF

2. Imaging of Seismogenic Asperities of the 2016 ML 6.0 Amatrice, Central Italy, Earthquake Through Dynamic Rupture Simulations

Author: Hideo Aochi, Cedric Twardzik, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Wave propagation, Finite difference method, Boundary (topology), Fracture mechanics, Radius, Parameter space, 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, 13. Climate action, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, Fracture (geology), Scaling, Seismology, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Numerical simulations are carried out for the dynamic rupture and wave propagation process of the 24th August 2016 ML 6.0 Amatrice, Italy, earthquake, using a boundary domain method (BDM), a hybrid method of boundary integral equation and finite difference methods. Dynamic rupture parameters of two seismogenic asperities are searched by iterative search through the comparison of the near-field ground motions. The preferred models indicate two asperities, aligned at around 4–5 km depth and separated from each other as well as from the initial rupture point. This requires a few supplementary patches connecting them, and that are less energetic than the asperities. The asperities are characterized by a radius of 2–3 km in the south (first to rupture) and of 2–4 km in the north (second to rupture), and the corresponding fracture energies of the asperities are (25.35 ± 0.63) × 1012 J and (38.05 ± 7.91) × 1012 J, respectively. These values are consistent with the scaling relation extrapolated from various analyses of large earthquakes. Although the parameter space of the search is limited due to the numerical performance of the dynamic rupture simulation, the proposed simple characterization of the earthquakes source confirms the scaling relation in fracture energy of the seismogenic asperities, which is essential for constructing mechanical earthquake source models.
Published: 2020
Full Text: View/download PDF

3. Constraining Spatiotemporal Characteristics of Magma Migration at Piton De La Fournaise Volcano From Pre‐eruptive Seismicity

Author: Duputel, Z., Lengliné, O., Ferrazzini, V., Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Ecole et Observatoire des Sciences de la Terre (EOST), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Volcanology, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], volcano seismicity, Induced seismicity, 010502 geochemistry & geophysics, 01 natural sciences, Volcano Monitoring, Intrusion, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Research Letter, Magma Migration and Fragmentation, Solid Earth, Seismology, 0105 earth and related environmental sciences, magma migration, template matching, geography, Geological, Effusive Volcanism, geography.geographical_feature_category, Volcano Seismology, Research Letters, Piton de la Fournaise, Geophysics, Volcano, 13. Climate action, Magma, General Earth and Planetary Sciences, Natural Hazards, Geology
Abstract: Volcano‐tectonic seismicity has been recorded for decades on various volcanoes and is linked with the magma transport and reservoir pressurization. Yet earthquakes often appear broadly distributed such that magma movement is difficult to infer from its analysis. We explore the seismicity that occurred before eruptions at Piton de la Fournaise in the last 5 years. Using template matching and relocation techniques, we produce a refined image of the summit seismicity, demonstrating that most earthquakes are located on a ring structure. However, only a portion of this structure is activated before each eruption, which provides an indication as to the direction of the future eruptive site. Furthermore, we show that the delay between the pre‐eruptive swarm and the eruption onset is proportional to the distance of the eruptive fissures relative to the summit cone. This reveals that the beginning of the intrusion already bears information regarding the future eruption location., Key Points We use a template matching technique to detect and relocate earthquakes during the 13 last eruptive unrests at Piton de la Fournaise volcanoAlmost all detected events are located on a ring‐shaped structure, corresponding to an area of weakness in the upper edifice of the volcanoThe location and timing of pre‐eruptive seismic swarms on this ring‐shaped structure bring information on the future eruptive site
Published: 2019
Full Text: View/download PDF

4. Interseismic Loading of Subduction Megathrust Drives Long‐Term Uplift in Northern Chile

Author: Quentin Bletery, Romain Jolivet, Zacharie Duputel, J.-A. Olive, Harsha S. Bhat, Mark Simons, Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Seismological Laboratory, California Institute of Technology, California Institute of Technology (CALTECH), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Laboratoire de géologie de l'ENS (LGE), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Division of Geological and Planetary Sciences [Pasadena], Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 010504 meteorology & atmospheric sciences, Deformation (mechanics), Subduction, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Crust, Active fault, 010502 geochemistry & geophysics, 01 natural sciences, Physics::Geophysics, Stress (mechanics), Geophysics, [SDU]Sciences of the Universe [physics], 13. Climate action, Interferometric synthetic aperture radar, General Earth and Planetary Sciences, Convergent boundary, Forearc, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: International audience; Large earthquakes are the product of elastic stress that has accumulated over decades to centuries along segments of active faults. Assuming an elastic crust, one can roughly estimate the location and rate of accumulation of elastic stress. However, this general framework does not account for inelastic, irrecoverable deformation, which results in large‐scale topography. We do not know over which part of the earthquake cycle such deformation occurs. Using InSAR and GNSS measurements, we report on a potential correlation between long‐term, inelastic vertical rate and short‐term, interseismic vertical rate in northern Chile. Approximately 4% to 8% of the geodetically derived interseismic vertical rates translate into permanent deformation, suggesting that topography of the forearc builds up during the interseismic period. This observation provides a quantitative basis for an improved understanding of the interplay between short‐term and long‐term dynamics along convergent plate boundaries.
Published: 2020
Full Text: View/download PDF

5. Depth varying rupture properties during the 2015 Mw 7.8 Gorkha (Nepal) earthquake

Author: Cunren Liang, Bryan Riel, Eric J. Fielding, Jean-Paul Ampuero, Junle Jiang, Zacharie Duputel, Susan Owen, Sergey Samsonov, Han Yue, Mark Simons, Angelyn Moore, Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Seismological Laboratory, Canada Centre for Mapping and Earth Observation, Natural Resources Canada (CCMEO), and CNRS PICS, IDEX attractivité
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Synthetic aperture radar, 010504 meteorology & atmospheric sciences, Subduction, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Thrust, Kinematics, Slip (materials science), 010502 geochemistry & geophysics, Collision, Geodesy, 01 natural sciences, Tectonics, Geophysics, Interferometric synthetic aperture radar, Geology, Seismology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: International audience; On April 25th 2015, the Mw 7.8 Gorkha (Nepal) earthquake ruptured a portion of the Main Himalayan Thrust underlying Kathmandu and surrounding regions. We develop kinematic slip models of the Gorkha earthquake using both a regularized multi-time-window (MTW) approach and an unsmoothed Bayesian formulation, constrained by static and high rate GPS observations, synthetic aperture radar (SAR) offset images, interferometric SAR (InSAR), and teleseismic body wave records. These models indicate that Kathmandu is located near the updip limit of fault slip and approximately 20 km south of the centroid of fault slip. Fault slip propagated unilaterally along-strike in an ESE direction for approximately 140 km with a 60 km cross-strike extent. The deeper portions of the fault are characterized by a larger ratio of high frequency (0.03–0.2 Hz) to low frequency slip than the shallower portions. From both the MTW and Bayesian results, we can resolve depth variations in slip characteristics, with higher slip roughness, higher rupture velocity, longer rise time and higher complexity of subfault source time functions in the deeper extents of the rupture. The depth varying nature of rupture characteristics suggests that the up-dip portions are characterized by relatively continuous rupture, while the down-dip portions may be better characterized by a cascaded rupture. The rupture behavior and the tectonic setting indicate that the earthquake may have ruptured both fully seismically locked and a deeper transitional portions of the collision interface, analogous to what has been seen in major subduction zone earthquakes.
Published: 2017
Full Text: View/download PDF

6. The Alland earthquake sequence in Eastern Austria: Shedding light on tectonic stress geometry in a key area of seismic hazard

Author: Schippkus, Sven, Hausmann, Helmut, Duputel, Zacharie, Bokelmann, Götz, University of Vienna [Vienna], Zentralanstalt für Meteorologie und Geodynamik (ZAMG), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 010504 meteorology & atmospheric sciences, Eastern Alps, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 010502 geochemistry & geophysics, 01 natural sciences, moment tensor inversion, aftershocks, Sequence (geology), Tectonics, Seismic hazard, earthquake, Key (cryptography), General Earth and Planetary Sciences, tectonics, Tectonic stress, Geology, Aftershock, Seismology, 0105 earth and related environmental sciences, General Environmental Science
Abstract: We present our results on the fault geometry of the Alland earthquake sequence in eastern Austria (Eastern Alps) and discuss its implications for the regional stress regime and active tectonics. The series contains 71 known events with local magnitudes 0.1 ≤ M L ≤ 4.2 that occurred in between 2016 and 2017. We locate the earthquakes in a regional 3D velocity model to find absolute locations. These locations are then refined by relocating all events relative to each other using a double-difference approach, based on relative travel times measured from waveform cross-correlation and catalogue data. We also invert for the moment tensor of the M L = 4.2 mainshock by fitting synthetic waveforms to the recorded seismo-grams using a combination of the L1- and L2-norms of the waveform differences. Direct comparison of waveforms of the largest events in the sequence suggests that all of them ruptured with very similar mechanisms. We find that the sequence ruptured a reverse fault, that is dipping with ~30° towards ~north-northeast (NNE) at 6–7 km depth. This is supported by both the hypocentres and the mainshock source mechanism. The fault is most likely located in the buried basement of the Bohemian massif, the “Bohemian Spur”. This (reverse) fault has a nearly perpendicular orientation to the normal-fault structures of the Vienna Basin Transfer Fault System further east at a shallower depth, indicating a lateral stress decoupling that can also act as a vertical stress decoupling in some places. In the west, earthquakes (at a larger depth within the upper crust) show compressive stresses, whereas the Vienna Basin to the east shows extensional (normal-faulting) stress. This provides insight into the regional stress field and its spatial variation, and it helps to better understand earthquakes in the area, including the “1590 Ried am Riederberg” earthquake.
Published: 2019
Full Text: View/download PDF

7. Knots A GEOSCOPE and VOLCANO: review and outlook

Author: Pardo, Constanza, Saurel, Jean-Marie, Vallée, Martin, Lemarchand, Arnaud, Léger, Félix, Leroy, Nicolas, Satriano, Claudio, Guinet, Cyril, Bernard, Armelle, Lévêque, Jean-Jacques, Zigone, Dimitri, Pesqueira, Frédérick, Lejeune, Anne-Marie, Moretti, Roberto, Peltier, Aline, Le Friant, Anne, Komorowski, Jean-Christophe, Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Ecole et Observatoire des Sciences de la Terre (EOST), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire volcanologique et sismologique de martinique (OVSM), Institut de Physique du Globe de Paris, Observatoire Volcanologique et Sismologique de Guadeloupe (OVSG), Observatoire Volcanologique du Piton de la Fournaise (OVPF), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Volcan, Sismologie, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Système d'information, RESIF, Volcano, Information system, Seismology
Abstract: Résif seismological data are collected and validated by centres operated by Résif partners and are called "Knots A". The data are then transmitted to the Résif seismological data centre, also known as "Knot B". This poster reports the results from two of the Résif Knots A: Knot A VOLCANO and Knot A GEOSCOPE. Knot A VOLCANO concentrates seismic data from the three volcanological and seismological observatories of the Institut de Physique du Globe de Paris. These observatories operate analogue short-period, three-component digital short-period, digital medium-band and digital broadband seismological stations. These data are used for monitoring regional volcanic and telluric activity, as well as for tsunami warning. Knot A GEOSCOPE validates and transmits data from the GEOSCOPE Broadband Seismological Station Observatory to Knot B, representing more than 35 years of seismological (since 1982) and accelerometric (since 2012) data. This poster, presented during the Résif 2019 Scientific and Technical Meetings in Biarritz, presents the results at the end of 2019 and the perspectives of these nodes, in the framework of the Résif deployment. Résif is a national research infrastructure dedicated to the observation and understanding of the Earth's internal structure and dynamics. Résif is based on high technology observation networks, composed of seismological, geodetic and gravimetric instruments deployed densely throughout France. The data collected allow the study of ground deformation, surface and deep structures, local and global seismicity and natural hazards, particularly seismic, on the French territory with a high spatio-temporal resolution. Résif is integrated into the European (EPOS - European Plate Observing System) and worldwide instruments that allow to image the Earth's interior in its entirety and to study numerous natural phenomena.; Les données sismologiques Résif sont collectées et validées par des centres opérés par des partenaires Résif et sont appelés « nœuds A ». Les données sont ensuite transmises au centre de données sismologiques Résif, appelé aussi « nœud B ». Ce poster fait état des résultats de deux des noeuds A de Résif : le nœud A VOLCANO et le nœud A GEOSCOPE. Le nœud A VOLCANO concentre les données sismiques des trois observatoires volcanologiques et sismologiques de l'Institut de Physique du Globe de Paris. Ces observatoires opèrent des stations sismologiques courte-période analogique, courte-période numérique trois composantes, moyenne-bande numérique et large-bande numérique. Ces données sont utilisées pour le suivi de l’activité volcanique et tellurique régionale, ainsi que pour l’alerte aux tsunamis. Le nœud A GEOSCOPE valide et transmet au nœud B les données de l'observatoire de stations sismologiques large bande GEOSCOPE, ce qui représente plus de 35 ans de données sismologiques (depuis 1982) et accélérométriques (depuis 2012). Ce poster, présenté lors des Rencontres scientifiques et techniques Résif 2019 à Biarritz, présente le bilan fin 2019 et les perspectives de ces nœuds, dans le cadre du déploiement de Résif. Résif est une infrastructure de recherche nationale dédiée à l’observation et la compréhension de la structure et de la dynamique Terre interne. Résif se base sur des réseaux d’observation de haut niveau technologique, composés d’instruments sismologiques, géodésiques et gravimétriques déployés de manière dense sur tout le territoire français. Les données recueillies permettent d’étudier avec une haute résolution spatio-temporelle la déformation du sol, les structures superficielles et profondes, la sismicité à l’échelle locale et globale et les aléas naturels, et plus particulièrement sismiques, sur le territoire français. Résif s’intègre aux dispositifs européens (EPOS - European Plate Observing System) et mondiaux d’instruments permettant d’imager l’intérieur de la Terre dans sa globalité et d’étudier de nombreux phénomènes naturels.
Published: 2019

8. The long recurrence intervals of small repeating earthquakes may be due to the slow slip rates of small fault strands

Author: Olivier Lengliné, J. C. Hawthorne, J. R. Williams, Department of Earth Sciences [Oxford], University of Oxford [Oxford], Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: musculoskeletal diseases, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Seismic slip, Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, General Earth and Planetary Sciences, Aseismic slip, Fault slip, Scaling, Seismology, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Slip rate
Abstract: Observations since 1998 have revealed that repeating earthquakes, and particularly small repeating earthquakes, occur less often than expected given their seismically derived slip and the regional fault slip rate. Here we test the hypothesis that small repeaters occur infrequently because they occur on fault segments or strands with low slip rates. We analyze the recurrence interval-moment scaling of earthquake sequences near Parkfield, California. We find that closely spaced sequences, which likely occur on the same fault strand and respond to the same slip rate, follow a M1/30 scaling consistent with seismic slip rates while widely spaced sequences, which likely occur on different strands, follow a M0.170 scaling consistent with the previous counterintuitive observations. These results suggest that spatially varying slip rates could create the M0.170 recurrence interval scaling, though we cannot exclude other explanations.
Published: 2019
Full Text: View/download PDF

9. The 2007 Caldera Collapse of Piton de la Fournaise Volcano: Source Process from Very-Long-Period Seismic Signals

Author: Zacharie Duputel, Luis Rivera, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: bepress|Physical Sciences and Mathematics, 010504 meteorology & atmospheric sciences, bepress|Physical Sciences and Mathematics|Earth Sciences, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], EarthArXiv|Physical Sciences and Mathematics|Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, bepress|Physical Sciences and Mathematics|Earth Sciences|Geophysics and Seismology, Geochemistry and Petrology, Long period, Earth and Planetary Sciences (miscellaneous), medicine, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Caldera, caldera collapse, Collapse (medical), 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, geography.geographical_feature_category, magma reservoir processes, Subsidence, surface waves, EarthArXiv|Physical Sciences and Mathematics, Piton de la Fournaise, Geophysics, Volcano, Space and Planetary Science, 13. Climate action, single force source, Magma, EarthArXiv|Physical Sciences and Mathematics|Earth Sciences|Geophysics and Seismology, medicine.symptom, Seismology, Geology
Abstract: In April 2007, Piton de la Fournaise volcano experienced its largest caldera collapse in at least 300 yr. This event consisted of a series of 48 subsidence increments characterized by very-long-period (VLP) seismic signals equivalent to M w 4.4 to 5.4. Source analysis of VLP events suggests a piston-like mechanism with a collapsing crack source corresponding to the contraction of the magma reservoir and a single force representing the collapse of the above rock column. We show that the collapse dynamics is primarily controlled by magma withdrawal from the reservoir, which was likely in a bubbly state at the time of the event. Similar to the 2018 Kilauea collapse, we observe a reduction of the time-interval between successive subsidence increments, which results from the acceleration of magma withdrawal and a progressive weakening of the edifice at the beginning of the sequence.
Published: 2019
Full Text: View/download PDF

10. SeismoCitizen : Un projet combinant les approches de la sismologie et des sciences humaines basé sur le déploiement d'un réseau sismique dense et peu coûteux hébergé par les citoyens

Author: Schlupp, Antoine, Chavot, Philippe, Grunberg, Marc, Bes De Berc, Maxime, Jund, Hélène, Ajak, Fanny, Vergne, Jerôme, Masson, Frédéric, Schmittbuhl, J., Ecole et Observatoire des Sciences de la Terre (EOST), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Sismologie (IPGS) (IPGS-Sismologie), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire Interuniversitaire des Sciences de l'Education et de la Communication (LISEC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Université de Lorraine (UL), EGU, Bertrand, Véronique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Station sismologique, [SHS.SOCIO]Humanities and Social Sciences/Sociology, Seismic noise, [SHS.SOCIO] Humanities and Social Sciences/Sociology, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], RESIF, Seismological station, Bruit sismique, Sismologie, Sociology, Sociologie, Participatory sciences, [SDU.STU.GP] Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Sciences participatives, Seismology
Abstract: This poster presents the multidisciplinary project of citizen seismology, called SismoCitoyen, led by Eost, LISEC and SAGE. The project aims to build a real network of observation sites in urban and peri-urban areas, among private volunteers who also participate in a survey conducted by sociologists. Requiring no technical expertise, the equipment installed by Eost makes it possible to increase the mesh size of permanent institutional observation sites and thus improve seismicity detection and characterization, as well as the characterization of the associated seismic risk. They also aim to improve seismological imaging of the subsoil, in particular by passive methods based on seismic noise analysis. This type of experimentation is likely to increase and the modalities for integrating data into the Résif research infrastructure information system are being studied. The seismometer model used allows the host (or his relatives) to consult the recorded data online and in real time. This is where the "social sciences" component of the project comes in, which aims to observe and analyse the effects of citizen involvement in scientific research (via the hosting of a seismometer) on the perception and representations of seismology and micro-seismicity phenomena. LISEC and SAGE are conducting this study via two interviews, one during the installation of the seismometer and the other six to eight months later. The first operational phase of the project took place at the beginning of 2019 with the deployment of 25 stations in the Mulhouse region (Haut-Rhin). The SismoCitoyen project involves the BCSF-RENASS, a national observation service run by Eost, as well as IPGS, LISEC and SAGE. It is financially supported by the CNRS, the University of Strasbourg and the LabEx G-Eau-Thermie profonde., Ce poster présente le projet pluridisciplinaire de sismologie citoyenne, baptisé SismoCitoyen, conduit par l'Eost, le LISEC et le SAGE. Le projet vise à construire un véritable réseau de sites d’observation en milieu urbain et péri-urbain, chez des particuliers volontaires qui participent également à une enquête menée par des sociologues. Ne demandant aucune compétence technique, les équipements installés par l'Eost permettent de densifier le maillage des sites d’observation institutionnels permanents et, ainsi, d’améliorer la détection et la caractérisation de la sismicité, ainsi que la caractérisation du risque sismique associé. Ils visent également à améliorer l’imagerie sismologique du sous-sol, en particulier par des méthodes passives basées sur l’analyse du bruit sismique. Ce type d'expérimentation est appelé à se multiplier et les modalités d'intégration des données dans le système d'information de l'infrastructure de recherche Résif sont à l'étude. Le modèle de sismomètre utilisé permet à celui qui l’héberge (ou ses proches) de consulter en ligne et en temps réel les données enregistrées. C'est là qu'intervient le volet « sciences sociales » du projet, qui vise à observer et analyser les effets d’un engagement citoyen dans la recherche scientifique (via l’hébergement d’un sismomètre) sur la perception et les représentations de la sismologie et des phénomènes de micro-sismicité. Ce sont le LISEC et le SAGE qui conduisent cette étude via deux entretiens, l’un lors de l’installation du sismomètre, l’autre six à huit mois plus tard. La première phase opérationnelle du projet s'est déroulée en début d'année 2019 avec le déploiement de 25 stations dans la région de Mulhouse (Haut-Rhin). Le projet SismoCitoyen implique le BCSF-RENASS, service national d’observation porté par l'Eost, ainsi que l'IPGS, le LISEC et le SAGE. Il est soutenu financièrement par le CNRS, l’Université de Strasbourg et le LabEx G-Eau-Thermie profonde.
Published: 2019

11. Seafloor spreading event in western Gulf of Aden during the November 2010–March 2011 period captured by regional seismic networks: evidence for diking events and interactions with a nascent transform zone

Author: Kassim Mohamed, Cécile Doubre, Ismael Al-Ganad, Jamal Sholan, Derek Keir, Julie Perrot, Abdulhakim Ahmed, Sylvie Leroy, Abayazid Ahmadine, Khaled Khanbari, Frédérique Rolandone, Eric Jacques, Jérôme Vergne, Alexandre Nercessian, Laurence Audin, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), The Arta Geophysical Observatory, National Oceanography Centre [Southampton] (NOC), University of Southampton, Centre d’Etudes et de Recherche de Djibouti (CERD), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Sismologie (IPGS) (IPGS-Sismologie), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Sana'a University, Seismological and Volcanological Observatory Center, Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), The Arta Geophysical Observatory (OGA), Domaines Océaniques (LDO), Centre National de la Recherche Scientifique (CNRS)-Institut d'écologie et environnement-Observatoire des Sciences de l'Univers-Université de Brest (UBO)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de Recherche pour le Développement (IRD), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Yemen Remote Sensing Center and Department of Earth and Environmental Science, Yemen Geological Survey & Mineral Ressources Board, GSMRB, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre d'études et de recherches scientifiques de Djibouti (CERD), Centre d'études et de recherches scientifiques de Djibouti, Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Dynamics: seismotectonics, Earthquake source observations, Mid-ocean ridge processes, Seismicity and tectonics, Submarine tectonics and volcanism, Transform faults, Geophysics, Geochemistry and Petrology, Dike, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], seismotectonics [Dynamics], [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Induced seismicity, 010502 geochemistry & geophysics, 01 natural sciences, 0105 earth and related environmental sciences, geography, Rift, geography.geographical_feature_category, Transform fault, Seafloor spreading, Ridge, Magma, Seismic moment, Seismology, Geology
Abstract: In November 2010, intense seismic activity including 29 events with a magnitude above 5.0, started in the western part of the Gulf of Aden, where the structure of the oceanic spreading ridge is characterized by a series of N115◦-trending slow-spreading segments set within an EW-trending rift. Using signals recorded by permanent and temporary networks in Djibouti and Yemen, we located 1122 earthquakes, with a magnitude ranging from 2.1 to 5.6 from 2010 November 1 to 2011 March 31. By looking in detail at the space–time distribution of the overall seismicity, and both the frequency and the moment tensor of large earthquakes, we re-examine the chronology of this episode. In addition, we also interpret the origin of the activity using high-resolution bathymetric data, as well as from observations of seafloor cable damage caused by high temperatures and lava flows. The analysis allows us to identify distinct active areas. First, we interpret that this episode is mainly related to a diking event along a specific ridge segment, located at E044◦. In light of previous diking episodes in nearby subaerial rift segments, for which field constraints and both seismic and geodetic data exist, we interpret the space–time evolution of the seismicity of the first few days. Migration of earthquakes suggests initial magma ascent below the segment centre. This is followed by a southeastward dike propagation below the rift immediately followed by a northwestward dike propagation below the rift ending below the northern ridge wall. The cumulative seismic moment associated with this sequence reaches 9.1 × 1017 Nm, and taking into account a very low seismic versus geodetic moment, we estimate a horizontal opening of ∼0.58–2.9 m. The seismic activity that followed occurred through several bursts of earthquakes aligned along the segment axis, which are interpreted as short dike intrusions implying fast replenishment of the crustal magma reservoir feeding the dikes. Over the whole period, the opening is estimated to be ∼1.76–8.8 m across the segment. A striking feature of this episode is that the seismicity remained confined within one individual segment, whereas the adjacent en-echelon segments were totally quiescent, suggesting that the magma supply system of one segment is disconnected from those of the neighbouring segments. Second, we identify activity induced by the first intrusion with epicentres aligned along an N035◦E-trending, ∼30 km long at the northwestern end of the active opening segment. This group encompasses more than seven earthquakes with magnitude larger than 5.0, and with strike-slip focal mechanisms consistent with the faults identified in the bathymetry and the structural pattern of the area. We propose that a transform fault is currently in formation which indicates an early stage of the ridge segmentation, at the locus of the trend change of the spreading ridge, which also corresponds to the boundary between a clear oceanic lithosphere and the zone of transform between continental and oceanic crust.
Published: 2016
Full Text: View/download PDF

12. Global finite-frequency S-wave delay-times: how much crust matters

Author: Luis Rivera, Frédéric Dubois, S. Lambotte, Christophe Zaroli, Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Wave propagation, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Body waves, Crust, 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Geochemistry and Petrology, Seismic tomography, S-wave, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: We investigate the influence of crust on time residual measurements made by cross-correlation in the 10–51 s filtering period range on a global scale, considering two crustal models: CRUST2.0 and CRUST1.0. This study highlights, in a quantitative way, crust-related time corrections. One part of this correction is directly linked to the body wave traveltime through the crust as predicted by the ray theory, whereas a second part is related to interferences with multiple crustal reflections. This second component, called finite-frequency (FF) crustal correction, is frequency-dependent unlike the ray-theory based correction. We show that if this frequency-dependent crust-related correction is not taken into account in cross-correlation measurements, it may lead to a dispersive effect in S-wave delay-times that could ultimately bias tomographic models. On average, this FF correction increases with the filtering period. Comparisons between the two crustal models highlight the significant dispersive effect of the crust, which has complex patterns depending on geological contexts, with an important role of the sediment thickness. Although ray crustal corrections remain important, FF crustal effects may lead to a bias in measurements if not properly taken into account; on average they may reach 0.9–1.6 s for CRUST2.0 and 0.5–1.6 s for CRUST1.0, for period ranging from 10 to 51 s, respectively.
Published: 2019
Full Text: View/download PDF

13. Azimuthal anisotropy in the wider Vienna basin region: a proxy for the present-day stress field and deformation

Author: Rafael Abreu, Edi Kissling, Thomas Plenefisch, Luděk Vecsey, Götz Bokelmann, Glenn Cougoulat, K. Kuk, H. Munzarová, Michael Korn, Jaroslava Plomerová, M. Bès De Berc, Zoltán Gráczer, K. Fischer, Domenico Giardini, T Fiket, Milena Moretti, Viktor Wesztergom, Simon Besançon, Daniele Spallarossa, M. Vallocchia, R. Voigt, S. Schippkus, A. Cavaliere, A. Nardi, Marco Massa, ETHZ-Sed Electronics Lab, Sven Schippkus, Thomas Meier, Irene Molinari, Claudia Piromallo, Wolfgang Friederich, B. Klotz, S. Funke, M. Santulin, Goetz Bokelmann, Lucia Margheriti, Zoltán Wéber, S. Ueding, Davide Piccinini, J. Kotek, Damiano Pesaresi, György Hetényi, Iva Dasović, Anne Paul, Yan Jia, Maria-Theresia Apoloner, Stefano Solarino, Silvia Pondrelli, M. Reiss, Wayne C Crawford, M. Čarman, S. Danesi, Joachim R. R. Ritter, Jean-Xavier Dessa, C. Maron, R. Daniel, I. Allegretti, C. Aubert, W. Scherer, A. Dannowski, Petr Kolínský, Claudio Chiarabba, S. Prevolnik, S. Egdorf, John Clinton, Vesna Šipka, Ezio D'Alema, Florian Fuchs, Marc Régnier, L. Métral, G. Szanyi, Simone Salimbeni, Hélène Jund, Mladen Živčić, Marijan Herak, D. Malengros, Heidrun Kopp, Frederik Tilmann, E. Szücs, Christine Thomas, J. Huber, Catherine Péquegnat, David Wolyniec, J. Chèze, Joachim Wassermann, T. Czifra, L. Cristiano, J. Loos, Christian Weidle, D. Jarić, Cécile Doubre, R. Racine, Stefan Wiemer, L. Kühne, Aladino Govoni, Sara Lovati, S. Klingen, Josip Stipčević, Kathrin Spieker, F. Wolf, Dimitri Zigone, P. Jedlička, G. Weyland, D. Petersen, Dietrich Lange, Davorka Herak, S. Heimers, Gidera Gröschl, D. Brunel, J. Pahor, T. Zieke, Martin Thorwart, Anne Deschamps, Xavier Martin, M. Capello, Georg Rümpker, D. Schulte-Kortnack, B. Heit, F. Mazzarini, B. Süle, Angelo Strollo, Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Seismic anisotropy, 010504 meteorology & atmospheric sciences, Seismic noise, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Seismic interferometry, Present day, 010502 geochemistry & geophysics, 01 natural sciences, Azimuth, Stress field, Europe, Geophysics, Geochemistry and Petrology, Vienna basin, Surface waves and free oscillations, Anisotropy, ComputingMilieux_MISCELLANEOUS, Geology, Seismology, 0105 earth and related environmental sciences
Abstract: SUMMARYWe infer seismic azimuthal anisotropy from ambient-noise-derived Rayleigh waves in the wider Vienna Basin region. Cross-correlations of the ambient seismic field are computed for 1953 station pairs and periods from 5 to 25 s to measure the directional dependence of interstation Rayleigh-wave group velocities. We perform the analysis for each period on the whole data set, as well as in overlapping 2°-cells to regionalize the measurements, to study expected effects from isotropic structure, and isotropic–anisotropic trade-offs. To extract azimuthal anisotropy that relates to the anisotropic structure of the Earth, we analyse the group velocity residuals after isotropic inversion. The periods discussed in this study (5–20 s) are sensitive to crustal structure, and they allow us to gain insight into two distinct mechanisms that result in fast orientations. At shallow crustal depths, fast orientations in the Eastern Alps are S/N to SSW/NNE, roughly normal to the Alps. This effect is most likely due to the formation of cracks aligned with the present-day stress-field. At greater depths, fast orientations rotate towards NE, almost parallel to the major fault systems that accommodated the lateral extrusion of blocks in the Miocene. This is coherent with the alignment of crystal grains during crustal deformation occurring along the fault systems and the lateral extrusion of the central part of the Eastern Alps.
Published: 2019
Full Text: View/download PDF

14. Impulsive Source of the 2017 M

Author: Elham Shabani, Baptiste Gombert, Romain Jolivet, James Hollingsworth, Zacharie Duputel, Luis Rivera, Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of Geophysics, University of Tehran, Sismologie (IPGS) (IPGS-Sismologie), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Grenoble Alpes (UGA)-Université Gustave Eiffel-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris)
Subjects: 010504 meteorology & atmospheric sciences, Continental collision, Earthquake Source Observations, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Satellite Geodesy: Results, Slip (materials science), Active fault, 010502 geochemistry & geophysics, 01 natural sciences, Radio Science, earthquake source physics, Earthquake Dynamics, Interferometric synthetic aperture radar, Research Letter, tectonics, Zagros Thrust and Fold Belt, Geodesy and Gravity, Seismic risk, Solid Earth, Seismology, Earthquake Interaction, Forecasting, and Prediction, 0105 earth and related environmental sciences, Research Letters, Seismic Cycle Related Deformations, Tectonic Deformation, Tectonics, Geophysics, Interferometry, Epicenter, General Earth and Planetary Sciences, Seismicity and Tectonics, Zagros fold and thrust belt, Geology
Abstract: On 12 November 2017, a M W=7.3 earthquake struck near the Iranian town of Ezgeleh, at the Iran‐Iraq border. This event was located within the Zagros fold and thrust belt which delimits the continental collision between the Arabian and Eurasian Plates. Despite a high seismic risk, the seismogenic behavior of the complex network of active faults is not well documented in this area due to the long recurrence interval of large earthquakes. In this study, we jointly invert interferometric synthetic aperture radar and near‐field strong motions to infer a kinematic slip model of the rupture. The incorporation of these near‐field observations enables a fine resolution of the kinematic rupture process. It reveals an impulsive seismic source with a strong southward rupture directivity, consistent with significant damage south of the epicenter. We also show that the slip direction does not match plate convergence, implying that some of the accumulated strain must be partitioned onto other faults., Key Points The Ezgeleh earthquake ruptured a flat thrust fault in the Zagros fold and thrust beltKinematic slip modeling reveals a highly impulsive source with southward directivity, possibly causing the large damage in the areaThe direction of coseismic slip suggests a strain partitioning between thrust and unmapped strike‐slip faults
Published: 2018
Full Text: View/download PDF

15. Strain budget of the Ecuador–Colombia subduction zone: A stochastic view

Author: Eric J. Fielding, Romain Jolivet, B. Gombert, Luis Rivera, Junle Jiang, Zacharie Duputel, Cunren Liang, Mark Simons, Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Institute of Geophysics and Planetary Physics [San Diego] (IGPP), Scripps Institution of Oceanography (SIO), University of California [San Diego] (UC San Diego), University of California-University of California-University of California [San Diego] (UC San Diego), University of California-University of California, Jet Propulsion Laboratory (JPL), and NASA-California Institute of Technology (CALTECH)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 010504 meteorology & atmospheric sciences, Subduction, business.industry, Geodetic datum, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Kinematics, Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Interferometric synthetic aperture radar, Earth and Planetary Sciences (miscellaneous), Global Positioning System, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Spatial variability, business, Geology, Smoothing, Seismology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: The 2016 Pedernales earthquake (M_W=7.8) ruptured a portion of the Colombia–Ecuador subduction interface where several large historical earthquakes have been documented since the great 1906 earthquake (M=8.6). Considering all significant ruptures that occurred in the region, it has been suggested that the cumulative moment generated co-seismically along this part of the subduction over the last century exceeds the moment deficit accumulated inter-seismically since 1906. Such an excess challenges simple models with earthquakes resetting the elastic strain accumulated inter-seismically in locked asperities. These inferences are however associated with large uncertainties that are generally unknown. The impact of spatial smoothing constraints on co-seismic and inter-seismic models also prevents any robust assessment of the strain budget. We propose a Bayesian kinematic slip model of the 2016 Pedernales earthquake using the most comprehensive dataset to date including InSAR and GPS offsets, tsunami waveforms, and kinematic records from high-rate GPS and strong-motions. In addition, we use inter-seismic geodetic velocities to produce a probabilistic inter-seismic coupling model of the subduction interface. Our stochastic co-seismic and inter-seismic solutions include the ensemble of all plausible models consistent with our prior information and that fit the observations within uncertainties. The analysis of these model ensembles indicates that an excess of co-seismic moment during the 1906–2016 period is likely in Central Ecuador only if we assume that 1942 and 2016 earthquakes are colocated. If this assumption is relaxed, we show that this conclusion no longer holds given uncertainties in co- and inter-seismic processes. The comparison of 1942 and 2016 teleseismic records reveals large uncertainties in the location of the 1942 event, hampering our ability to draw strong conclusions on the unbalanced moment budget in the region. Our results also show a heterogeneous coupling of the subduction interface that coincides with two slip asperities in our co-seismic model for the 2016 Pedernales earthquake and with the location of historical ruptures in 1958, 1979 and 1998. The spatial variability in coupling and complexity in earthquake history suggest strong heterogeneities in frictional properties of the subduction megathrust.
Published: 2018
Full Text: View/download PDF

16. Revisiting the 1992 Landers earthquake: a Bayesian exploration of co-seismic slip and off-fault damage

Author: Cécile Doubre, Mark Simons, Zacharie Duputel, Luis Rivera, B. Gombert, Romain Jolivet, Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Sismologie (IPGS) (IPGS-Sismologie), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Institut de physique du globe de Strasbourg ( IPGS ), Université de Strasbourg ( UNISTRA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Sismologie, Université de Strasbourg ( UNISTRA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Strasbourg ( UNISTRA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de géologie de l'ENS ( LGE ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Département des Géosciences - ENS Paris, École normale supérieure - Paris ( ENS Paris ) -École normale supérieure - Paris ( ENS Paris ), California Institute of Technology ( CALTECH ), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de géologie de l'ENS (LGE), and École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 010504 meteorology & atmospheric sciences, business.industry, Seismic slip, Bayesian probability, Inversion (geology), [ SDU.STU.TE ] Sciences of the Universe [physics]/Earth Sciences/Tectonics, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, Physics::Geophysics, Shear modulus, Geophysics, [ PHYS.PHYS.PHYS-GEO-PH ] Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 13. Climate action, Geochemistry and Petrology, Global Positioning System, business, Smoothing, Aftershock, Seismology, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Existing models for the distribution of subsurface fault slip associated with the 1992 Landers, CA, earthquake (M_w = 7.3) show significant dissimilarities. In particular, they exhibit different amounts of slip at shallow depths (
Published: 2018
Full Text: View/download PDF

17. The 2015 Gorkha earthquake: A large event illuminating the Main Himalayan Thrust fault

Author: Zacharie Duputel, Véronique Farra, Gérard Wittlinger, György Hetényi, Luis Rivera, Jérôme Vergne, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut des sciences de la terre [Lausanne] (ISTE), Université de Lausanne (UNIL), and IDEX attractivité
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, Focal mechanism, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Subduction, Hypocenter, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Fault (geology), 010502 geochemistry & geophysics, 01 natural sciences, Shock (mechanics), Geophysics, 13. Climate action, Receiver function, Earthquake source observations, Subduction zones, Body waves, Surface waves and free oscillations, Main Himalayan Thrust, 2015 Gorkha earthquake, receiver function, earthquake source observations, fault geometry, focal mechanism, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, General Earth and Planetary Sciences, Thrust fault, Aftershock, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: International audience; The 2015 Gorkha earthquake sequence provides an outstanding opportunity to better characterize the geometry of the Main Himalayan Thrust (MHT). To overcome limitations due to unaccounted lateral heterogeneities, we perform Centroid Moment Tensor inversions in a 3-D Earth model for the main shock and largest aftershocks. In parallel, we recompute S-toP and P-to-S receiver functions from the Hi-CLIMB data set. Inverted centroid locations fall within a low-velocity zone at 10–15 km depth and corresponding to the subhorizontal portion of the MHT that ruptured during the Gorkha earthquake. North of the main shock hypocenter, receiver functions indicate a north dipping feature that likely corresponds to the midcrustal ramp connecting the flat portion to the deep part of the MHT. Our analysis of the main shock indicates that long-period energy emanated updip of high-frequency radiation sources previously inferred. This frequency-dependent rupture process might be explained by different factors such as fault geometry and the presence of fluids.
Published: 2016
Full Text: View/download PDF

18. Reservoir Imaging Using Ambient Noise Correlation From a Dense Seismic Network

Author: A. Le Chenadec, Maximilien Lehujeur, Jean Schmittbuhl, Jérôme Vergne, Dimitri Zigone, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Ecole et Observatoire des Sciences de la Terre (EOST), Zigone, Dimitri, Fond de Recherche en Géothermie Profonde - - G-EAU-TERMIE PROFONDE2011 - ANR-11-LABX-0050 - LABX - VALID, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), and ANR-11-LABX-0050,G-EAU-TERMIE PROFONDE,Fond de Recherche en Géothermie Profonde(2011)
Subjects: 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Ambient noise level, Geophone, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Seismic noise, 010502 geochemistry & geophysics, 01 natural sciences, symbols.namesake, Wavelength, Geophysics, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Surface wave, Earth and Planetary Sciences (miscellaneous), symbols, Group velocity, [SDU.STU.GP] Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Rayleigh wave, Geothermal gradient, Geology, Seismology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: International audience; In September 2014, a dense temporary seismic network (EstOF) including 288 single-component geophones was deployed during 1 month in the Outre-Forêt region of the Upper Rhine Graben (France), where two deep geothermal projects (Soultz-sous-Forêts and Rittershoffen) are currently in operation. We apply ambient seismic noise correlation to estimate the empirical Green’s function of the medium between the ~41,200 station pairs in the network. The noise correlation functions obtained are comparable to those from previous studies based on the sparse long-term networks settled in the area mostly to monitor the induced seismic activity. However, the dense spatial coverage of the EstOF network improves our ability toidentify the main phases of the Green’s function. Both the fundamental mode and the ﬁrst overtone of the Rayleigh waves are identiﬁed between most station pairs. P waves are also evidenced. We analyze the statistical distribution of the Rayleigh wave group velocity between station pairs as a function of the period (between 0.8 and 5 s), the station pair orientation, the distance over wavelength ratio and the signal-to-noise ratio. From these observations, we build a high-resolution three-dimensional S wave velocity model of the upper crust (down to 3 km deep) around the regional deep geothermal reservoirs. This model is consistent with local geological structures but also evidences nonlithological variations, particularly at depth in thebasement. These variations are interpreted as large-scale temperature anomalies related to deep hydrothermal circulation.
Published: 2018
Full Text: View/download PDF

19. Ambient-noise tomography of the wider Vienna Basin region

Author: Schippkus, Sven, Zigone, Dimitri, Bokelmann, Götz, Hetenyi, György, Abreu, Rafael, Allegretti, Ivo, Apoloner, Maria-Theresia, Aubert, Coralie, Besancon, Simon, Bes de Berc, Maxime, Brunel, Didier, Capello, Marco, Carman, Martina, Cavaliere, Adriano, Cheze, Jerome, Chiarabba, Claudio, Clinton, John, Cougoulat, Glenn, Crawford, Wayne C., Cristiano, Luigia, Czifra, Tibor, D'Alema, Ezio, Danesi, Stefania, Daniel, Romuald, Dannowski, Anke, Dasovic, Iva, Deschamps, Anne, Dessa, Jean-Xavier, Doubre, Cecile, Egdorf, Sven, Fiket, Tomislav, Fischer, Kasper, Friederich, Wolfgang, Fuchs, Florian, Funke, Sigward, Giardini, Domenico, Govoni, Aladino, Graczer, Zoltan, Gröschl, Gidera, Heimers, Stefan, Heit, Ben, Herak, Davorka, Huber, Johann, Jaric, Dejan, Jedlicka, Petr, Jia, Yan, Jund, Helene, Kissling, Edi, Klingen, Stefan, Klotz, Bernhard, Kolinsky, Petr, Kopp, Heidrun, Korn, Michael, Kotek, Josef, Kühne, Lothar, Kuk, Kreso, Lange, Dietrich, Loos, Jürgen, Lovati, Sara, Malengros, Deny, Margheriti, Lucia, Maron, Christophe, Martin, Xavier, Massa, Marco, Mazzarini, Francesco, Meier, Thomas, Metral, Laurent, Molinari, Irene, Moretti, Milena, Munzarova, Helena, Nardi, Anna, Pahor, Jurij, Paul, Anne, Pequegnat, Catherine, Petersen, Daniel, Pesaresi, Damiano, Piccinini, Davide, Piromallo, Claudia, Plenefisch, Thomas, Plomerova, Jaroslava, Pondrelli, Silvia, Prevolnik, Snjezan, Racine, Roman, Regnier, Marc, Reiss, Miriam, Ritter, Joachim, Rümpker, Georg, Salimbeni, Simone, Santulin, Marco, Scherer, Werner, Schulte-Kortnack, Detlef, Sipka, Vesna, Solarino, Stefano, Spallarossa, Daniele, Spieker, Kathrin, Stipcevic, Josip, Strollo, Angelo, Süle, Balint, Szanyi, Gyöngyver, Szücs, Eszter, Thomas, Christine, Thorwart, Martin, Tilmann, Frederik, Ueding, Stefan, Vallocchia, Massimiliano, Vecsey, Ludek, Voigt, Rene, Wassermann, Joachim, Weber, Zoltan, Weidle, Christian, Wesztergom, Viktor, Weyland, Gauthier, Wiemer, Stefan, Wolf, Felix Noah, Wolyniec, David, Zieke, Thomas, Zivcic, Mladen, Institut für Meteorologie und Geophysik [Wien] (IMGW), Universität Wien, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Seismic noise, Wave propagation, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Seismic interferometry, Fault (geology), Crustal structure, 010502 geochemistry & geophysics, 01 natural sciences, Physics::Geophysics, symbols.namesake, Geochemistry and Petrology, Rayleigh wave, Dispersion (water waves), Crustal imaging, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Seismic tomography, Tectonics, Geophysics, symbols, Seismology, Geology
Abstract: International audience; We present a new 3-D shear-velocity model for the top 30 km of the crust in the wider Vienna Basin region based on surface waves extracted from ambient-noise cross-correlations. We use continuous seismic records of 63 broad-band stations of the AlpArray project to retrieve interstation Green's functions from ambient-noise cross-correlations in the period range from 5 to 25 s. From these Green's functions, we measure Rayleigh group traveltimes, utilizing all four components of the cross-correlation tensor, which are associated with Rayleigh waves (ZZ, RR, RZ and ZR), to exploit multiple measurements per station pair. A set of selection criteria is applied to ensure that we use high-quality recordings of fundamental Rayleigh modes. We regionalize the interstation group velocities in a 5 km × 5 km grid with an average path density of ∼20 paths per cell. From the resulting group-velocity maps, we extract local 1-D dispersion curves for each cell and invert all cells independently to retrieve the crustal shear-velocity structure of the study area. The resulting model provides a previously unachieved lateral resolution of seismic velocities in the region of ∼15 km. As major features, we image the Vienna Basin and Little Hungarian Plain as low-velocity anomalies, and the Bohemian Massif with high velocities. The edges of these features are marked with prominent velocity contrasts correlated with faults, such as the Alpine Front and Vienna Basin transfer fault system. The observed structures correlate well with surface geology, gravitational anomalies and the few known crystalline basement depths from boreholes. For depths larger than those reached by boreholes, the new model allows new insight into the complex structure of the Vienna Basin and surrounding areas, including deep low-velocity zones, which we image with previously unachieved detail. This model may be used in the future to interpret the deeper structures and tectonic evolution of the wider Vienna Basin region, evaluate natural resources, model wave propagation and improve earthquake locations, among others.
Published: 2018
Full Text: View/download PDF

20. Knot A GEOSCOPE: review and prospects

Author: Pardo, Constanza, Vallee, Martin, Bonaime, Sébastien, Stutzmann, Eléonore, Bernard, Armelle, Lévêque, Jean-Jacques, Zigone, Dimitri, Leroy, Nicolas, Pesqueira, Frédérick, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Ecole et Observatoire des Sciences de la Terre (EOST), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), RESIF, Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Sismologie, Sismologie large bande, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Système d'information, RESiF, Information System, Réseau sismologique, Seismological network, GEOSCOPE, Seismology
Abstract: Knot A GEOSCOPE validates and transmits to node B of the RESIF information system the data from the GEOSCOPE broadband seismological station observatory, which represents: 35 years of data (1.8 TB): seismological (since 1982) and accelerometric (since 2012), temperature and pressure, and 31 real-time stations, over 400 operational channels sampled at 100Hz, 20Hz and 1Hz.This poster presents the results and prospects of this node at the end of 2017, as part of the RESIF deployment. The French Seismological and Geodetic Network RESIF is a national research infrastructure dedicated to the observation and understanding of the structure and dynamics of the Internal Earth. RESIF is based on high-tech observation networks, composed of seismological, geodetic and gravimetric instruments deployed in a dense manner throughout France. The data collected make it possible to study with high spatial and temporal resolution the deformation of the ground, surface and deep structures, seismicity on a local and global scale and natural hazards, and more particularly seismic events, on French territory. RESIF is integrated into European (EPOS - European Plate Observing System) and global systems of instruments for imaging the Earth's interior as a whole and studying many natural phenomena. The GEOSCOPE Observatory, created in 1982, consists of a network of 33 seismological stations in 18 countries, whose instrumentation and maintenance are carried out in collaboration between the IPGP and the EOST in Strasbourg. The IPGP data centre is responsible for data management and distribution. The data are also distributed by the national RESIF data centre and by IRIS-DMC. The GEOSCOPE Observatory aims to provide broadband seismological data from its 33 stations to the French and international scientific community. GEOSCOPE is therefore an important component of the global seismological network, which allows analyses of the earth's structure, seismic noise, and earthquake process (see the quick information provided by GEOSCOPE on global earthquakes of magnitude greater than 5.5-6).; Le Nœud A GEOSCOPE valide et transmet au nœud B du système d'information RESIF les données de l'observatoire de stations sismologiques large bande GEOSCOPE, ce qui représente : 35 ans de données (1,8 To) : sismologiques (depuis 1982) et accéléromètriques (depuis 2012), température et pression, et 31 stations en temps réel, plus de 400 canaux opérationnels échantillonnés à 100Hz, 20Hz et 1Hz.Ce poster présente le bilan et les perspectives de ce noeud A fin 2017, dans le cadre du déploiement de RESIF. Le Réseau sismologique et géodésique français RESIF est une infrastructure de recherche nationale dédiée à l’observation et la compréhension de la structure et de la dynamique Terre interne. RESIF se base sur des réseaux d’observation de haut niveau technologique, composés d’instruments sismologiques, géodésiques et gravimétriques déployés de manière dense sur tout le territoire français. Les données recueillies permettent d’étudier avec une haute résolution spatio-temporelle la déformation du sol, les structures superficielles et profondes, la sismicité à l’échelle locale et globale et les aléas naturels, et plus particulièrement sismiques, sur le territoire français. RESIF s’intègre aux dispositifs européens (EPOS - European Plate Observing System) et mondiaux d’instruments permettant d’imager l’intérieur de la Terre dans sa globalité et d’étudier de nombreux phénomènes naturels. L'Observatoire GEOSCOPE, créé en 1982, est constitué d'un réseau de 33 stations sismologiques réparties dans 18 pays, dont l'instrumentation et la maintenance sont réalisées au sein d'une collaboration entre l'IPGP et l'EOST à Strasbourg. Le centre de données de l'IPGP assure la gestion des données et leur distribution. Les données sont également distribuées par le centre national de données RESIF et par IRIS-DMC. L'Observatoire GEOSCOPE a pour but de fournir les données sismologiques large-bande de ses 33 stations à la communauté scientifique française et internationale. GEOSCOPE est donc une composante importante du réseau sismologique mondial, qui permet des analyses de la structure terrestre, du bruit sismique, et du processus des tremblements de Terre (voir les informations rapides fournies par GEOSCOPE sur les séismes mondiaux de magnitude supérieure à 5.5-6).
Published: 2017

21. Magnitude Mw in metropolitan France

Author: Yves Cansi, Bertrand Delouis, Michel Cara, Antoine Schlupp, Marylin Denieul, Olivier Sèbe, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Géoazur (GEOAZUR 6526), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Détection et de Géophysique (CEA) (LDG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction des Applications Militaires (DAM), Ecole et Observatoire des Sciences de la Terre (EOST), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 2019) (UNS), and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 021110 strategic, defence & security studies, 0211 other engineering and technologies, Magnitude (mathematics), 02 engineering and technology, Induced seismicity, 010502 geochemistry & geophysics, 01 natural sciences, Moment (mathematics), Metropolitan France, Geophysics, Seismic hazard, Amplitude, Geochemistry and Petrology, Linear regression, Range (statistics), Geology, Seismology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: The recent seismicity catalogue of metropolitan France Sismicite Instrumentale de l’Hexagone (SI-Hex) covers the period 1962–2009. It is the outcome of a multipartner project conducted between 2010 and 2013. In this catalogue, moment magnitudes (M w) are mainly determined from short-period velocimetric records, the same records as those used by the Laboratoire de Detection Geophysique (LDG) for issuing local magnitudes (M L) since 1962. Two distinct procedures are used, whether M L-LDG is larger or smaller than 4. For M L-LDG >4, M w is computed by fitting the coda-wave amplitude on the raw records. Station corrections and regional properties of coda-wave attenuation are taken into account in the computations. For M L-LDG ≤4, M w is converted from M L-LDG through linear regression rules. In the smallest magnitude range M L-LDG
Published: 2017
Full Text: View/download PDF

22. Long-period analysis of the 2016 Kaikoura earthquake

Author: Zacharie Duputel, Luis Rivera, Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Initiative d’Excellence (IDEX)
Subjects: Earthquake, 010504 meteorology & atmospheric sciences, Physics and Astronomy (miscellaneous), [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, Strike-slip, Interplate earthquake, Long period, Thrust fault, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Subduction, Astronomy and Astrophysics, Strike-slip tectonics, Surface waves, Geophysics, 13. Climate action, Space and Planetary Science, Intraplate earthquake, Episodic tremor and slip, Megathrust, Seismology, Geology, New Zealand
Abstract: The recent M w = 7.8 Kaikoura (New Zealand) earthquake involved a remarkably complex rupture propagating in an intricate network of faults at the transition between the Alpine fault in the South Island and the Kermadec-Tonga subduction zone. We investigate the main features of this complicated rupture process using long-period seismological observations. Apparent Rayleigh-wave moment-rate functions reveal a clear northeastward directivity with an unusually weak rupture initiation during 60 s followed by a major 20 s burst of moment rate. To further explore the rupture process, we perform a Bayesian exploration of multiple point-source parameters in a 3-D Earth model. The results show that the rupture initiated as a small strike-slip rupture and propagated to the northeast, triggering large slip on both strike-slip and thrust faults. The Kaikoura earthquake is thus a rare instance in which slip on intraplate faults trigger extensive interplate thrust faulting. This clearly outlines the importance of accounting for secondary faults when assessing seismic and tsunami hazard in subduction zones.
Published: 2017
Full Text: View/download PDF

23. A review of methods for determining stress fields from earthquakes focal mechanisms; Application to the Sierentz 1980 seismic crisis (Upper Rhine graben)

Author: Julie Maury, François Cornet, Louis Dorbath, Géophysique expérimentale (IPGS) (IPGS-GE), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Sismologie (IPGS) (IPGS-Sismologie)
Subjects: Breakout, Inversion method, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, Borehole, Inverse transform sampling, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Geology, Inversion (meteorology), Stress field, Focal mechanisms, 010502 geochemistry & geophysics, 01 natural sciences, R-value (insulation), Confidence interval, Graben, Upper Rhine graben, Seismology, 0105 earth and related environmental sciences
Abstract: The inversion of earthquake focal mechanisms is one of the few tools available for determining principal stress directions at seismogenic depths. Various methods have been proposed for performing such inversions. For three of the most commonly used methods, including one that has been proposed by Jacques Angelier, we discuss the physical assumptions and the error determination and then we propose an extension for one of the methods. All four methods are then applied for evaluating the stress field in the Upper Rhine graben. They are applied to seismic data recorded with a temporary monitoring network that was deployed 12 hours after the magnitude Mw = 4.4 Sierentz earthquake, which occurred on July 15, 1980. While differences in principal stress directions can be as much as 28° depending on the method used for the principal stress direction determination (orientation of the minimum principal stress has been found to range from N051°E with a 27° plunge to N090° E with a 20° plunge), the 90% confidence level associated with each method varies from 11° to 27°. Moreover, these various methods yield fairly diverse values for the R factor that characterizes relative differences between principal stress magnitudes (from R = 0.7 with a 0.2 90% confidence level to R = 0.3 with a 0.2 90% confidence level). Furthermore all three methods leave some focal mechanisms unexplained. These are then declared to be the result of heterogeneity and are not considered for the inversion. It is concluded that earthquake focal mechanisms inversions lack resolution for stress field evaluation at depth if no proper attention is given to the event independence hypothesis. When proper attention is given to this hypothesis, a resolution of the order of 15° may be achieved. The minimum principal stress orientation derived with these various focal mechanisms inversions differs by 4 to 36° from the orientation determined from borehole breakouts observed in Basel, in a 5 km deep well (N054°E ± 14°), located some 20 km from Sierentz. The solution that fits best borehole breakout observations is that which satisfies the minimum number (three) of prerequisite physical assumptions.
Published: 2013
Full Text: View/download PDF

24. Characteristic atmosphere–ocean–solid earth interactions in the Antarctic coastal and marine environment inferred from seismic and infrasound recording at Syowa Station, East Antarctica

Author: Yoshiaki Ishihara, Alessia Maggi, Eléonore Stutzmann, Masa-yuki Yamamoto, Genti Toyokuni, Masaki Kanao, National Institute of Polar Research [Tokyo] (NiPR), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), National Astronomical Observatory, National Institutes of Natural Sciences [Tokyo] (NINS), Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), KUT, Kochi University of Technology (KUT), Research Center for Prediction of Earthquakes and Volcanic Eruptions, Tohoku University [Sendai], and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Seismometer, Microseism, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, Infrasound, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Geology, Ocean Engineering, Storm, 010502 geochemistry & geophysics, 01 natural sciences, Latitude, Microbarom, Amplitude, 13. Climate action, Climatology, Wind wave, 14. Life underwater, Seismology, 0105 earth and related environmental sciences, Water Science and Technology
Abstract: International audience; Several characteristic waves detected by seismographs in Antarctic stations have been recognized as originating from the physical interaction between the solid earth and the atmosphere-ocean-cryosphere system surrounding the Antarctic and may be used as a proxy for characterizing ocean wave climate. A Chaparral-type infrasound sensor was installed at Syowa Station (SYO; 39.6E, 69.0S), East Antarctica, in April 2008 during the International Polar Year (IPY2007-2008). Matching data are also available for this time period from the existing broadband seismic recorder located close by. Continuous infrasound data for 2008-2009 include background signals (microbaroms) with a broad peak in the wave period between the values of 4 and 10 s. Signals with the same period are recorded by the broadband seismograph at SYO (microseisms). This period band is identified as double-frequency microseisms/baroms (DFM). The DFM have relatively lower amplitudes during winter. We suggest that this is due to the sea-ice extent around the coast causing a decreased ocean loading effect. In contrast, the single frequency microseisms/baroms with a peak in period between 12 and 30 s are observed under storm conditions, particularly in winter. On the infrasound data, stationary signals are identified with harmonic overtones at a few Hertz to lowermost human audible band, which we suggest is due to local effects such as sea-ice cracking and vibration. Microseism measurements are a useful proxy for characterizing ocean wave climate, complementing other oceanographic and geophysical data. At SYO, continuous monitoring by both broadband seismograph and infrasound contributes to the Federation of Digital Seismographic Networks, the Comprehensive Nuclear-Test-Ban Treaty in the high southern latitudes and the Pan-Antarctic Observations System under the Scientific Committee on Antarctic Research.
Published: 2013
Full Text: View/download PDF

25. Note: Localization based on estimated source energy homogeneity

Author: Knut Jørgen Måløy, Eirik Grude Flekkøy, Olivier Lengliné, Fredrik Kvalheim Eriksen, Guillaume Daniel, Renaud Toussaint, Semih Turkaya, Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Magnitude, Research and Development, CGG Veritas, Hugues, Department of Physics [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO), ITN FLOWTRANS, and European Project: 316889,EC:FP7:PEOPLE,FP7-PEOPLE-2012-ITN,FLOWTRANS(2013)
Subjects: 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Acoustics, Accelerometer, seismology, 01 natural sciences, Arrival time, localization, acoustic, Lamb waves, 0103 physical sciences, 010306 general physics, Instrumentation, 0105 earth and related environmental sciences, Physics, Attenuation, Inversion (meteorology), methodology, Acoustic source localization, technique, [PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph], Amplitude, Minification, signal, laboratory, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract: International audience; Acoustic signal localization is a complex problem with a wide range of industrial and academic applications. Herein, we propose a localization method based on energy attenuation and inverted source amplitude comparison (termed estimated source energy homogeneity, or ESEH). This inversion is tested on both synthetic (numerical) data using a Lamb wave propagation model, and experimental 2D plate data (recorded with 4 accelerometers sensitive up to 26 kHz). We compare the performance of this technique with classic source localization algorithms: arrival time localization, time reversal localization, and localization based on energy amplitude. Our technique is highly versatile, and out-performs the conventional techniques in terms of error minimization and cost (both computational and financial).
Published: 2016
Full Text: View/download PDF

26. Diverse rupture processes in the 2015 Peru deep earthquake doublet

Author: Zacharie Duputel, Lingling Ye, Zhongwen Zhan, Thorne Lay, Hiroo Kanamori, Seismological Laboratory, California Institute of Technology, California Institute of Technology (CALTECH), Department of Earth and Planetary Sciences [Santa Cruz], University of California [Santa Cruz] (UCSC), University of California-University of California, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and CNRS PICS, IDEX attractivité
Subjects: History, Geological Phenomena, 010504 meteorology & atmospheric sciences, Hypocenter, Magnitude (mathematics), [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 010502 geochemistry & geophysics, seismology, 01 natural sciences, History, 21st Century, Theoretical, Lithosphere, Models, S-wave, Peru, Earthquakes, Humans, Earthquake rupture, Aftershock, Research Articles, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Multidisciplinary, Subduction, geophysics, rupture process, SciAdv r-articles, Models, Theoretical, 21st Century, deep earthquakes, Geophysics, 13. Climate action, Seismic moment, Geology, Seismology, Research Article
Abstract: The nearby Mw 7.5 and Mw 7.6 events in a deep earthquake doublet under Peru have diverse stress drops and radiation efficiency., Earthquakes in deeply subducted oceanic lithosphere can involve either brittle or dissipative ruptures. On 24 November 2015, two deep (606 and 622 km) magnitude 7.5 and 7.6 earthquakes occurred 316 s and 55 km apart. The first event (E1) was a brittle rupture with a sequence of comparable-size subevents extending unilaterally ~50 km southward with a rupture speed of ~4.5 km/s. This earthquake triggered several aftershocks to the north along with the other major event (E2), which had 40% larger seismic moment and the same duration (~20 s), but much smaller rupture area and lower rupture speed than E1, indicating a more dissipative rupture. A minor energy release ~12 s after E1 near the E2 hypocenter, possibly initiated by the S wave from E1, and a clear aftershock ~165 s after E1 also near the E2 hypocenter, suggest that E2 was likely dynamically triggered. Differences in deep earthquake rupture behavior are commonly attributed to variations in thermal state between subduction zones. However, the marked difference in rupture behavior of the nearby Peru doublet events suggests that local variations of stress state and material properties significantly contribute to diverse behavior of deep earthquakes.
Published: 2016
Full Text: View/download PDF

27. Lithospheric structure of Taiwan from gravity modelling and sequential inversion of seismological and gravity data

Author: Cheinway Hwang, Maxime Mouyen, Maximilien Lehujeur, Catherine Dorbath, Yih-Min Wu, Fanny Ponton, Frédéric Masson, Dynamique globale et déformation active (IPGS) (IPGS-DGDA), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Sismologie (IPGS) (IPGS-Sismologie)
Subjects: Gravity (chemistry), 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, seismic tomography, Taiwan, simultaneous inversion, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 010502 geochemistry & geophysics, 01 natural sciences, Gravity anomaly, Physics::Geophysics, Sequential model, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth-Surface Processes, Geodesy, gravity, Geophysics, Gravity model of trade, Seismic tomography, Anomaly (physics), Geology, Bouguer anomaly, Seismology, Free-air gravity anomaly
Abstract: Using a Bouguer anomaly map and a dense seismic data set, we have performed two studies in order to improve our knowledge of the deep structure of Taiwan. First, we model the Bouguer anomaly along a profile crossing the island using simple forward modelling. The modelling is 2D, with the hypothesis of cylindrical symmetry. Second we present a joint analysis of gravity anomaly and seismic arrival time data recorded in Taiwan. An initial velocity model has been obtained by local earthquake tomography (LET) of the seismological data. The LET velocity model was used to construct an initial 3D gravity model, using a linear velocity–density relationship (Birch's law). The synthetic Bouguer anomaly calculated for this model has the same shape and wavelength as the observed anomaly. However some characteristics of the anomaly map are not retrieved. To derive a crustal velocity/density model which accounts for both types of observations, we performed a sequential inversion of seismological and gravity data. The variance reduction of the arrival time data for the final sequential model was comparable to the variance reduction obtained by simple LET. Moreover, the sequential model explained about 80% of the observed gravity anomaly. New 3D model of Taiwan lithosphere is presented.
Published: 2012
Full Text: View/download PDF

28. Stress Drop during Earthquakes: Effect of Fault Roughness Scaling

Author: François Renard, Emily E. Brodsky, Michel Bouchon, Jean Schmittbuhl, Thibault Candela, Mécanique des failles, Institut des Sciences de la Terre (ISTerre), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Department of Earth and Planetary Sciences [Santa Cruz], University of California [Santa Cruz] (UCSC), and University of California-University of California
Subjects: Physics, Length scale, 010504 meteorology & atmospheric sciences, Characteristic length, Drop (liquid), Geometry, Slip (materials science), Surface finish, 010502 geochemistry & geophysics, 01 natural sciences, Physics::Geophysics, Geophysics, Geochemistry and Petrology, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Deformation (engineering), Anisotropy, Scaling, Seismology, 0105 earth and related environmental sciences
Abstract: We propose that a controlling parameter of static stress drop during an earthquake is related to the scaling properties of the fault-surface topography. Using high resolution laser distance meters, we have accurately measured the roughness scaling properties of two fault surfaces in different geological settings (the French Alps and Nevada). The data show that fault-surface topography is scale dependent and may be accurately described by a self-affine geometry with a slight anisotropy characterized by two extreme roughness exponents ( H R ), H ||=0.6 in the direction of slip and H ⊥=0.8 perpendicular to slip. Disregarding plastic processes like rock fragmentation and focusing on elastic deformation of the topography, which is the dominant mode at large scales, the stress drop is proportional to the deformation, which is a spatial derivative of the slip. The evolution of stress-drop fluctuations on the fault plane can be derived directly from the self-affine property of the fault surface, with the length scale ( λ ) as std Δσ ( λ )∝ λ H R -1. Assuming no characteristic length scale in fault roughness and a rupture cascade model, we show that as the rupture grows, the average stress drop, and its variability should decrease with increasing source dimension. That is for the average stress drop Δσ ( r )∝ r H R -1, where r is the radius of a circular rupture. This result is a direct consequence of the elastic squeeze of fault asperities that induces the largest spatial fluctuations of the shear strength before and after the earthquake at local (small) scales with peculiar spatial correlations.
Published: 2011
Full Text: View/download PDF

29. Quake Catalogs from an Optical Monitoring of an Interfacial Crack Propagation

Author: Knut Jørgen Måløy, M. Grob, Jean Schmittbuhl, Renaud Toussaint, Stéphane Santucci, L. Rivera, Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique de l'ENS Lyon (Phys-ENS), École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Department of Physics [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Induced seismicity, 01 natural sciences, Physics::Geophysics, microseismicity catalogs, Geochemistry and Petrology, 0103 physical sciences, medicine, 010306 general physics, 0105 earth and related environmental sciences, Quake (natural phenomenon), Microseism, Fissure, Fracture mechanics, Mechanics, Crack front dynamics, analog model, Geophysics, medicine.anatomical_structure, Shear (geology), Epicenter, Geology, Seismology, asperity, Asperity (materials science)
Abstract: International audience; Using an experimental setup which allows to follow optically the propagation of an interfacial crack front in a heterogeneous medium, we show that the fracture front dynamics is governed by local and irregular avalanches with large velocity fluctuations. Events defined as high velocity bursts are ranked in catalogs with analogous characteristics to seismicity catalogs: time of occurence, epicenter location and energy parameter (moment). Despite differences in the fracturing mode (opening for the experiments and shear rupture for earthquakes), in the acquisition mode and in the range of time scales, the distributions of moment and epicenter jumps in the experimental catalogs obey the same scaling laws with exponents similar to the corresponding distributions for earthquakes. The record-breaking event analysis also shows very strong similarities between experimental and real seismicity catalogs. The results suggest that the dynamics of crack propagation is controlled by the elastic interactions between microstructures within the material.
Published: 2009
Full Text: View/download PDF

30. Insights on earthquake triggering processes from early aftershocks of repeating microearthquakes

Author: Jean-Paul Ampuero, Olivier Lengliné, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Seismological Laboratory, and California Institute of Technology (CALTECH)
Subjects: 010504 meteorology & atmospheric sciences, San andreas fault, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Orders of magnitude (acceleration), Induced seismicity, 010502 geochemistry & geophysics, 01 natural sciences, Flattening, aftershocks, Earthquake catalog, Geophysics, Space and Planetary Science, Geochemistry and Petrology, bimaterial interface, Earth and Planetary Sciences (miscellaneous), Deconvolution, Seismology, Geology, Aftershock, 0105 earth and related environmental sciences
Abstract: International audience; Characterizing the evolution of seismicity rate of early aftershocks can yield important information about earthquake nucleation and triggering. However, this task is challenging because early aftershock seismic signals are obscured by those of the mainshock. Previous studies of early aftershocks employed high-pass filtering and template matching but had limited performance and completeness at very short times. Here we take advantage of repeating events previously identified on the San Andreas Fault at Parkfield and apply empirical Green's function deconvolution techniques. Both Landweber and sparse deconvolution methods reveal the occurrence of aftershocks as early as few tenths of a second after the mainshock. These events occur close to their mainshock, within one to two rupture lengths away. The aftershock rate derived from this enhanced catalog is consistent with Omori's law, with no flattening of the aftershock rate down to the shortest resolvable timescale ∼0.3 s. The early aftershock rate decay determined here matches seamlessly the decay at later times derived from the original earthquake catalog, yielding a continuous aftershock decay over timescales spanning nearly 8 orders of magnitude. Aftershocks of repeating microearthquakes may hence be governed by the same mechanisms from the earliest time resolved here, up to the end of the aftershock sequence. Our results suggest that these early aftershocks are triggered by relatively large stress perturbations, possibly induced by aseismic afterslip with very short characteristic time. Consistent with previous observations on bimaterial faults, the relative location of early aftershocks shows asymmetry along strike, persistent over long periods.
Published: 2015
Full Text: View/download PDF

31. SI-Hex: a new catalogue of instrumental seismicity for metropolitan France

Author: Delphine Leobal, Sophie Lambotte, Méric Haugmard, Christophe Maron, Marylin Denieul, Jérôme Van der Woerd, Yves Cansi, Bertrand Potin, Cécile Doubre, Bertrand Delouis, François Thouvenot, Marc Grunberg, Julie Perrot, Sophie Merrer, Olivier Sanchez, Pierre Arroucau, Jean-Paul Santoire, Michel Cara, Anne Deschamps, Antoine Schlupp, Katia Van Der Woerd, Marie Calvet, Matthieu Sylvander, Marc Nicolas, Antoine Mocquet, Arnaud Mignan, J. Guilbert, Sébastien Chevrot, Julien Fréchet, Liliane Jenatton, Olivia Golle, Stéphane Bruno, S. Godey, Eric Beucler, Nicole Béthoux, Alexandra Deboissy, Véronique Mendel, Olivier Sèbe, Marie Macquet, Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Détection et de Géophysique (CEA) (LDG), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 6526), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Dynamique terrestre et planétaire (DTP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), European Mediterranean Seismological Centre (EMSC/CSEM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Mécanique des failles, Institut des Sciences de la Terre (ISTerre), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Dynamique globale et déformation active (IPGS) (IPGS-DGDA), Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Seismicity, Magnitude (mathematics), Magnitude, Geology, Massif, Seismotectonics, Induced seismicity, 010502 geochemistry & geophysics, 01 natural sciences, Seismic hazard, Metropolitan France, Discrimination, Seismic moment, France, Seismology, 0105 earth and related environmental sciences
Abstract: The aim of the SI-Hex project (acronym for « Sismicité Instrumentale de l’Hexagone ») is to provide a catalogue of seismicity for metropolitan France and the French marine economic zone for the period 1962–2009 by taking into account the contributions of the various seismological networks and observatories from France and its neighbouring countries. The project has been launched jointly by the Bureau Central Sismologique Français (CNRS-University/BCSF) and the Laboratoire de Détection et de Géophysique (CEA-DAM/LDG). One of the main motivations of the project is to provide the end user with the best possible information on location and magnitude of each earthquake. So far, due to the various procedures in use in the observatories, the different locations and magnitudes of earthquakes located in the SI-Hex zone were presenting large discrepancies. In the 2014 version of the catalogue, 1D localizations of hypocentres performed with a unique computational scheme and covering the whole 1962–2009 period constitute the backbone of the catalogue (SI-Hex solutions). When available, they are replaced by more precise localizations made at LDG or, for recent times, by the regional observatories within: 1) the French Alps, 2) the southernmost Alps and the Mediterranean domain including Corsica, 3) the Pyrenees, and 4) the Armorican massif. Moment magnitudes Mw are systematically reported in the SI-Hex catalogue. They are computed from coda-wave analysis of the LDG records for most Mw>3.4 events, and are converted from local magnitudes ML for smaller magnitude events. Finally, special attention is paid to the question of discrimination between natural and artificial seismic events in order to produce a catalogue for direct use in seismic hazard analysis and seismotectonic investigations. The SI-Hex catalogue is accessible on the web site www.franceseisme.fr and contains 38,027 earthquake hypocentres, together with their seismic moment magnitudes Mw.
Published: 2015
Full Text: View/download PDF

32. Earthquake in a Maze: Compressional Rupture Branching During the 2012 M w 8.6 Sumatra Earthquake

Author: Lingsen Meng, Zacharie Duputel, Jean-Paul Ampuero, Joann M. Stock, Victor C. Tsai, Yingdi Luo, Seismological Laboratory, California Institute of Technology (CALTECH), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Division of Geological and Planetary Sciences [Pasadena]
Subjects: geography, Multidisciplinary, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Injury control, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, Seismotectonics, Poison control, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Moment magnitude scale, Fault (geology), 010502 geochemistry & geophysics, 01 natural sciences, High stress, 13. Climate action, Lithosphere, Source imaging, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: Earthquake in a Maze The 11 April 2012 magnitude 8.6 earthquake offshore of Sumatra was the largest measured earthquake along a strike-slip boundary that modern seismological instruments have ever recorded. Despite its size and proximity to a large population, there was no subsequent tsunami and there were no reported fatalities. Meng et al. (p. 724 , published online 19 July) used teleseismic data from seismological networks in Japan and Europe to image the source of high-frequency radiation generated by the earthquake to understand the mechanics of this unique event. The resultant back projections showed that the earthquake slowly ruptured along a complex series of faults. The deeper-than-usual rupture path and large stress drop are both features that may not be unique to this earthquake, suggesting that regions in a similar tectonic environment may have the potential for more complex—or larger—intraplate earthquakes than might have been expected.
Published: 2012
Full Text: View/download PDF

33. Aseismic slip and seismogenic coupling along the central San Andreas Fault

Author: Zheng-Kang Shen, Mark Simons, Piyush Agram, Romain Jolivet, Zacharie Duputel, Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of California [Los Angeles] (UCLA), and University of California
Subjects: Seismic gap, Synthetic aperture radar, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Magnitude (mathematics), [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Aseismic creep, Elastic-rebound theory, Fault (geology), 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Section (archaeology), Interferometric synthetic aperture radar, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, General Earth and Planetary Sciences, Geology, Seismology, 0105 earth and related environmental sciences
Abstract: International audience; We use high-resolution Synthetic Aperture Radar- and GPS-derived observations of surfacedisplacements to derive the first probabilistic estimates of fault coupling along the creeping section of theSan Andreas Fault, in between the terminations of the 1857 and 1906 magnitude 7.9 earthquakes. Usinga fully Bayesian approach enables unequaled resolution and allows us to infer a high probability ofsignificant fault locking along the creeping section. The inferred discreet locked asperities are consistentwith evidence for magnitude 6+ earthquakes over the past century in this area and may be associated withthe initiation phase of the 1857 earthquake. As creeping segments may be related to the initiation andtermination of seismic ruptures, such distribution of locked and creeping asperities highlights the centralrole of the creeping section on the occurrence of major earthquakes along the San Andreas Fault.
Published: 2015
Full Text: View/download PDF

34. The Iquique earthquake sequence of April 2014: Bayesian modeling accounting for prediction uncertainty

Author: Mark Simons, Sarah E. Minson, Junle Jiang, Susan Owen, Luis Rivera, Jean-Paul Ampuero, Romain Jolivet, F. H. Ortega Culaciati, Angelyn Moore, Bryan Riel, Sergey Samsonov, Zacharie Duputel, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL), Département des Géosciences - ENS Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Canada Centre for Mapping and Earth Observation, Natural Resources Canada (CCMEO), Departamento de Geofísica [Santiago], Universidad de Chile, and United States Geological Survey [Reston] (USGS)
Subjects: Seismic gap, 010504 meteorology & atmospheric sciences, Slow slip, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Slip (materials science), Bayesian inversion, 010502 geochemistry & geophysics, 01 natural sciences, Earthquake simulation, Prediction uncertainty, 1877 Chile seismic gap, Aftershock, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Subduction, 2014 Iquique earthquake, Geodesy, Foreshock, Geophysics, 13. Climate action, Trench, General Earth and Planetary Sciences, Episodic tremor and slip, Kinematic source model, Geology, Seismology
Abstract: International audience; The subduction zone in northern Chile is a well-identified seismic gap that last ruptured in 1877. On April 1, 2014, this region was struck by a large earthquake following a two-week-long series of foreshocks. This study combines a wide range of observations, including geodetic, tsunami and seismic data, to produce a reliable kinematic slip model of the Mw = 8.1 mainshock and a static slip model of the Mw= 7.7 aftershock. We use a novel Bayesian modeling approach that accounts for uncertainty in the Green's functions, both static and dynamic, while avoiding non-physical regularization. The results reveal a sharp slip zone, more compact than previously thought, located downdip of the foreshock sequence and up-dip of high-frequency sources inferred by back-projection analysis. Both the mainshock and the Mw = 7.7 aftershock did not rupture to the trench and left most of the seismic gap unbroken, leaving the possibility of a future large earthquake in the region.
Published: 2015
Full Text: View/download PDF

35. Fluid‐induced earthquakes with variable stress drop

Author: L. Lamourette, Jean Schmittbuhl, L. Vivin, Olivier Lengliné, Nicolas Cuenot, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), GEIE Exploitation Minière de la Chaleur, GEIE, Ecole et Observatoire des Sciences de la Terre (EOST), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and LABEX G-EAU-THERMIE PROFONDE
Subjects: [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Drop (liquid), Seismic slip, Geothermal reservoir, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Slip (materials science), Stress drop, earthquake scaling, Geophysics, Amplitude, Space and Planetary Science, Geochemistry and Petrology, geothermy, stress drop, Earth and Planetary Sciences (miscellaneous), Static stress, Waveform, Seismology, Geology, source parameters
Abstract: International audience; The static stress drop of an earthquake, which quantifies the ratio of seismic slip to the size of the rupture, is almost constant over several orders of magnitudes. Although variations are often observed, it is difficult, however, to attribute these variations either to a well-defined phenomenon or simply to measurement uncertainty. In this study we analyze the static stress drop of earthquakes that occurred during a water circulation test in the Soultz-sous-Forêts, France, geothermal reservoir in 2010. During this circulation test, 411 earthquakes were recorded, the largest event having a magnitude MD2.3. We show that several earthquakes in the reservoir can be combined into groups of closely located similar repeating waveforms. We infer that the amplitudes, and hence magnitudes, vary between the repeaters although the waveforms and spectra are both similar in shape. We measure similar corner frequencies for these events despite their different magnitudes, suggesting a similar rupture size. Our results imply that events at the same location may exhibit stress drop variations by as much as a factor of 300. We interpret that this variation in stress drop is caused by fluid pressure at the interface reducing the normal stress. We also hypothesize that the observed variations reflect a transition from stable to unstable slip on the imaged asperities.
Published: 2014
Full Text: View/download PDF

36. Global S-wave tomography using receiver pairs: an alternative to get rid of earthquake mislocation

Author: Christophe Zaroli, Zacharie Duputel, Bernhard S. A. Schuberth, Guust Nolet, Jean-Jacques Lévêque, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Ludwig-Maximilians-Universität München (LMU), Géoazur (GEOAZUR 7329), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA), SEISGLOB ANR 2011 Blanc SIMI 5-6-016-01,SEISGLOB ANR 2011 Blanc SIMI 5-6-016-01, European Project: 226837,EC:FP7:ERC,ERC-2008-AdG,GLOBALSEIS(2009), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA), Ecole et Observatoire des Sciences de la Terre (EOST), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut für Soziologie Ludwig-Maximilians-Universität München (LMU), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), ANR-11-BS56-0016,SEISGLOB,Imagerie globale du manteau terrestre en ondes S(2011), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Seismic tomography, Computer science, Earthquake source observations, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Physics::Geophysics, Azimuth, Reduction (complexity), Body waves, Geophysics, 13. Climate action, Geochemistry and Petrology, S-wave, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Tomography, Sensitivity (control systems), Differential (infinitesimal), Algorithm, Seismology, Earthquake location
Abstract: International audience; Global seismic tomography suffers from uncertainties in earthquake parameters routinely published in seismic catalogues. In particular, errors in earthquake location and origin-time may lead to strong biases in measured body wave delay-times and significantly pollute tomographic models. Common ways of dealing with this issue are to incorporate source parameters as additional unknowns into the linear tomographic equations, or to seek combinations of data to minimize the influence of source mislocations. We propose an alternative, physically-based method to desensitize direct S-wave delay-times to errors in earthquake location and origin-time. Our approach takes advantage of the fact that mislocation delay-time biases depend to first order on the earthquake-receiver azimuth, and to second order on the epicentral distance. Therefore, for every earthquake, we compute S-wave differential delay-times between optimized receiver pairs, such that a large part of their mislocation delay-time biases cancels out (for example origin-time fully subtracts out), while the difference of their sensitivity kernels remains sensitive to the model parameters of interest. Considering realistic, randomly distributed source mislocation vectors, as well as various levels of data noise and different synthetic Earths, we demonstrate that mislocation-related model errors are highly reduced when inverting for such differential delay-times, compared to absolute ones. The reduction is particularly rewarding for imaging the upper-mantle and transition zone. We conclude that using optimized receiver pairs is a suitable, low cost alternative to get rid of errors on earthquake location and origin-time for teleseismic direct S-wave traveltimes. Moreover, it can partly remove unilateral rupture propagation effects in cross-correlation delay-times, since they are similar to mislocation effects.
Published: 2014
Full Text: View/download PDF

37. The 2013 M_w 7.7 Balochistan Earthquake: Seismic Potential of an Accretionary Wedge

Author: Romain Jolivet, Bryan Riel, Sarah E. Minson, Mark Simons, Francois Ayoub, Mahdi Motagh, Luis Rivera, Michael Aivazis, Sebastien Leprince, H. Zhang, Eric J. Fielding, Zacharie Duputel, Sergey Samsonov, Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Natural Resources Canada (NRCan), GeoForschungsZentrum - Helmholtz-Zentrum Potsdam (GFZ), Jet Propulsion Laboratory (JPL), and NASA-California Institute of Technology (CALTECH)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Seismic gap, Accretionary wedge, 010504 meteorology & atmospheric sciences, Subduction, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, 13. Climate action, Geochemistry and Petrology, Interplate earthquake, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Thrust fault, Episodic tremor and slip, 2008 California earthquake study, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: International audience; Great earthquakes rarely occur within active accretionary prisms, despite the intense long‐term deformation associated with the formation of these geologic structures. This paucity of earthquakes is often attributed to partitioning of deformation across multiple structures as well as aseismic deformation within and at the base of the prism (Davis et al., 1983). We use teleseismic data and satellite optical and radar imaging of the 2013 Mw 7.7 earthquake that occurred on the southeastern edge of the Makran plate boundary zone to study this unexpected earthquake. We first compute a multiple point‐source solution from W‐phase waveforms to estimate fault geometry and rupture duration and timing. We then derive the distribution of subsurface fault slip from geodetic coseismic offsets. We sample for the slip posterior probability density function using a Bayesian approach, including a full description of the data covariance and accounting for errors in the elastic structure of the crust. The rupture nucleated on a subvertical segment, branching out of the Chaman fault system, and grew into a major earthquake along a 50° north‐dipping thrust fault with significant along‐strike curvature. Fault slip propagated at an average speed of 3.0 km/s for about 180 km and is concentrated in the top 10 km with no displacement on the underlying décollement. This earthquake does not exhibit significant slip deficit near the surface, nor is there significant segmentation of the rupture. We propose that complex interaction between the subduction accommodating the Arabia-Eurasia convergence to the south and the Ornach Nal fault plate boundary between India and Eurasia resulted in the significant strain gradient observed prior to this earthquake. Convergence in this region is accommodated both along the subduction megathrust and as internal deformation of the accretionary wedge.
Published: 2014
Full Text: View/download PDF

38. The Al Hoceima Mw 6.4 earthquake of 24 February 2004 and its aftershocks sequence

Author: Mohammed Menzhi, Farida Ousadou, Jérôme Van der Woerd, Michel Frogneux, Eric Jacques, Catherine Dorbath, Paul Tapponnier, Louis Dorbath, Youssef Hahou, H. Haessler, Bertrand Delouis, Dynamique globale et déformation active (IPGS) (IPGS-DGDA), Institut de physique du globe de Strasbourg (IPGS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Sismologie (IPGS) (IPGS-Sismologie), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), Centre de Recherche en Astronomie Astrophysique et Géophysique (CRAAG), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université Mohammed V de Rabat [Agdal] (UM5), Centre National de la Recherche Scientifique et Technologique (CNRST), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, Focal mechanism, geography.geographical_feature_category, Teleseismic inversion, Bedrock, Seismicity, Active fault, Slip (materials science), Induced seismicity, Focal mechanisms, Nappe, Geophysics, Sinistral and dextral, Aftershocks sequence, Al Hoceima, Tomography, Aftershock, Seismology, Geology, Earth-Surface Processes
Abstract: International audience; The Al Hoceima Mw 6.4 earthquake of 24 February 2004 that occurred in the eastern Rif region of Morocco already hit by a large event in May 1994 (Mw 5.9) has been followed by numerous aftershocks in the months following the event. The aftershock sequence has been monitored by a temporary network of 17 autonomous seismic stations during 15 days (28 March–10 April) in addition to 5 permanent stations of the Moroccan seismic network (CNRST, SPG, Rabat). This network allowed locating accurately about 650 aftershocks that are aligned in two directions, about N10-20E and N110-120E, in rough agreement with the two nodal planes of the focal mechanism (Harvard). The aftershock alignments are long enough, about 20 km or more, to correspond both to the main rupture plane. To further constrain the source of the earthquake main shock and aftershocks (mb > 3.5) have been relocated thanks to regional seismic data from Morocco and Spain. While the main shock is located at the intersection of the aftershock clouds, most of the aftershocks are aligned along the N10-20E direction. This direction together with normal sinistral slip implied by the focal mechanism is similar with the direction and mechanisms of active faults in the region, particularly the N10E Trougout oblique normal fault. Indeed, the Al Hoceima region is dominated by an approximate ENE-SSW direction of extension, with oblique normal faults. Three major 10–30 km-long faults, oriented NNE-SSW to NW-SE are particularly clear in the morphology, the Ajdir and Trougout faults, west and east of the Al Hoceima basin, respectively, and the NS Rouadi fault 20 km to the west. These faults show clear evidence of recent vertical displacements during the late Quaternary such as uplifted alluvial terraces along Oued Rihs, offset fan surfaces by the Rouadi fault and also uplifted and tilted abandoned marine terraces on both sides of the Al Hoceima bay.However, the N20E direction is in contrast with seismic sources identified from geodetic inversions, which favour but not exclusively the N110-120E rupture directions, suggesting that the 1994 and 2004 events occurred on conjugate faults. In any event, the recent seismicity is thus concentrated on sinistral N10-20E or N110-120E dextral strike-slip faults, which surface expressions remain hidden below the 3–5 km-thick Rif nappes, as shown by the tomographic images build from the aftershock sequence and the concentration of the seismicity below 3 km. These observations may suggest that strain decoupling between the thrusted cover and the underlying bedrock and highlights the difficulty to determine the source properties of moderate events with blind faults even in the case of good quality recorded data.
Published: 2014
Full Text: View/download PDF

39. Self-induced seismicity due to fluid circulation along faults

Author: Blanche Poisson, Hideo Aochi, Jean Schmittbuhl, Xavier Rachez, Renaud Toussaint, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Géophysique expérimentale (IPGS) (IPGS-GE), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Ecole et Observatoire des Sciences de la Terre (EOST), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, Borehole, Fracture and flow, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Induced seismicity, Fault zone rheology, 010502 geochemistry & geophysics, System of linear equations, 01 natural sciences, Tectonics, Earthquake dynamics, Geophysics, Rheology, Shear (geology), Geochemistry and Petrology, Rheology and friction of fault zones, Fluid dynamics, Lubrication, Permeability and porosity, ComputingMilieux_MISCELLANEOUS, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: International audience; In this article, we develop a system of equations describing fluid migration, fault rheology, fault thickness evolution and shear rupture during a seismic cycle, triggered either by tectonic loading or by fluid injection. Assuming that the phenomena predominantly take place on a single fault described as a finite permeable zone of variable width, we are able to project the equations within the volumetric fault core onto the 2D fault interface. From the basis of this "fault lubrication approximation", we simulate the evolution of seismicity when fluid is injected at one point along the fault to model induced seismicity during an injection test in a borehole that intercepts the fault. We perform several parametric studies to understand the basic behaviour of the system. Fluid transmissivity and fault rheology are key elements. The simulated seismicity generally tends to rapidly evolve after triggering, independently of the injection history and end when the stationary path of fluid flow is established at the outer boundary of the model. This self-induced seismicity takes place in the case where shear rupturing on a planar fault becomes dominant over the fluid migration process. On the contrary, if healing processes take place, so that the fluid mass is trapped along the fault, rupturing occurs continuously during the injection period. Seismicity and fluid migration are strongly influenced by the injection rate and the heterogeneity.
Published: 2014
Full Text: View/download PDF

40. Continuous Kurtosis-Based Migration for Seismic Event Detection and Location, with Application to Piton de la Fournaise Volcano, La Réunion

Author: Alessia Maggi, Florent Brenguier, Nadège Langet, Alberto Michelini, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Roma (INGV), Istituto Nazionale di Geofisica e Vulcanologia, Institut des Sciences de la Terre (ISTerre), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), European Project: 262330,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2010-1,NERA(2010), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)
Subjects: geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Induced seismicity, 010502 geochemistry & geophysics, Earthquake swarm, 01 natural sciences, Maxima and minima, Geophysics, Amplitude, Volcano, Geochemistry and Petrology, Kurtosis, Waveform, Geology, Sea level, Seismology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: We present an automatic earthquake detection and location technique based on migration of continuous waveform data. Data are preprocessed using a kurtosis estimator in order to enhance the first arrival information, then migrated onto a predefined search grid using precalculated P ‐wave travel times, and finally stacked. Local maxima in the resulting 4D space–time grid indicate the locations and origin times of seismic events. We applied our technique to earthquake swarms occurring on Piton de la Fournaise volcano, La Reunion, France. We located 5000 events from 12 different swarms that occurred between 2009 and 2011. Our automated locations are consistent with those performed using manual picks and indicate that the seismicity concentrates around sea level. Multiplet analysis of the detected events and subsequent double‐difference relocation produce sharper images of the earthquake swarms. Our code, Waveloc, is released in open source. Online Material: Figures of seismicity distributions from Waveloc, synthetic test, and stack amplitude values versus magnitudes.
Published: 2014
Full Text: View/download PDF

41. Small Scale Earthquake Mechanisms Induced by Fluid Injection at the Enhanced Geothermal System Reservoir Soultz (Alsace) in 2003 using Alternative Source Models

Author: Catherine Dorbath, Zuzana Jechumtálová, Jan Šílený, Institute of Geophysics of the Czech Academy of Sciences (IG / CAS), Czech Academy of Sciences [Prague] (CAS), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institute of Geophysics, Academy of sciences, Prague, Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)
Subjects: [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, Borehole, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Slip (materials science), Geophysics, Induced seismicity, Pure shear, Enhanced geothermal system, Permeability (earth sciences), Shear (geology), 13. Climate action, Geochemistry and Petrology, Seismic array, Geology, Seismology
Abstract: International audience; The geothermal reservoir at Soultz-sous-Forêts is a valuable natural laboratory for understanding the mechanisms of microearthquakes generated during stimulations and circulation tests. An ongoing effort currently exists regarding the retrieval of mechanisms aimed to indicate the type of fracturing of the rock massif. As a default, a moment tensor description has been applied. Nevertheless, the retrieval of the mode of fracturing still remains ambiguous. Recent studies indicate a prevailing shear slip but, rarely, a non-shear pattern has also been observed. The moment tensor, used today as a universal tool for descriptions of the mechanism, captures general balanced dipole sources. However, in the case of small-scale earthquakes, the moment tensor need not always be reliably determined. In an effort to fit the data, there may be notable non-shear components caused by the low quality of input data. Constraining the source model to directly determine a simpler one is convenient for describing the physical phenomena expected for a particular focus. An opening of new fractures can be described, to a first approximation, by a tensile crack, optionally combined with a shear slip. Such an alternative model is called a shear-tensile crack (STC) source model. The combination is practical, and can be used to both identify events that reflect purely mode-I (tensile) failure and to determine the dilation angle of the fracture undergoing shear. The latter is particularly important in enhanced geothermal system reservoirs such as Soultz, where shear-related dilation is believed to be the primary mechanism underpinning permeability creation during stimulation injections. We performed a synthetic case study by simulating seismic data as recorded by the actual seismic array installed at Soultz-sous-Forêts. Synthetic P and S amplitudes for several shear-tensile source models were inverted for several types of station coverage. The analysis explored how results were influenced by mislocation, mismodeling, and noise contamination of data. In most cases, the orientation of the mechanism was well resolved. Determination of shear vs. non-shear content within the mechanism was more difficult. From all of the factors influencing resolution that we explored, the quality of the monitoring system (the number of stations and their distribution with respect to the focus) and noise contamination were of the highest impact. The STC source model yielded considerably less spurious non-shear fracture components than the moment tensor. From the bulk of the seismicity recorded during the stimulation in 2003, we concentrated on the first phase of the injection when only a single borehole at the site was stimulated. We processed thirteen small earthquakes with magnitudes larger than 1.4 that were not treated in previous studies. We determined that their source mechanisms were dominantly pure shear slips on pre-existing faults, just as the earthquakes investigated earlier were. The results were also in agreement with the stress pattern from in situ measurements.
Published: 2014
Full Text: View/download PDF

42. Instrumental data on the seismic activity along the Dead Sea Transform

Author: Louis Dorbath, Catherine Dorbath, Abraham Hofstetter, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Garfunkel, Z. (ed.), Ben Avraham, Z. (ed.), and Kagan, E. (ed.)
Subjects: Dead sea, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Magnitude (mathematics), Crust, FAILLE TRANSFORMANTE, Induced seismicity, Structural basin, 010502 geochemistry & geophysics, 01 natural sciences, Stress drop, VARIATION TEMPORELLE, SEISME, VARIATION SPATIALE, Seismic moment, SISMOLOGIE, PROFONDEUR, Heat flow, Geology, Seismology, 0105 earth and related environmental sciences
Abstract: We analyzed the catalog of instrumental recordings of seismic activity from 1900 to 2010 along the Dead Sea Transform. The seismicity pattern reveals significant activity confined to 5 main sections of the transform. In all the sections of the transform there is a significant amount of seismic activity at depths of 9–10 km (lower part of the upper crust). The seismic activity extends to large depths of 20 km and more, where about 30 % of the seismic activity occurs in the lower crust, especially in the Dead Sea basin and the Arava Valley. The deep seismicity is correlative with previous low heat flow measurements along the transform, and thus suggesting a relatively cold crust. We analyzed more than 4,300 S-wave spectra of earthquakes in the magnitude range is 0.8 ≤ Md ≤ 6.2, with M0 values ranging from 3.1x1011 N · m to 5.4x1018 N · m, and Brune stress drop estimates, Δσ, between 0.1 MPa and 15 MPa. The total seismic moment release in the years 1900–2010 in the Dead Sea Transform due to all the earthquakes, including the earthquake in 1927, is only a fraction of the expected seismic moment release.
Published: 2014
Full Text: View/download PDF

43. The 2013, Mw 7.7 Balochistan earthquake, energetic strike-slip reactivation of a thrust fault

Author: Shengji Wei, Jean Philippe Avouac, Zacharie Duputel, Jean-Paul Ampuero, Donald V. Helmberger, Francois Ayoub, Romain Jolivet, Sebastien Leprince, Lingsen Meng, Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Seismological Laboratory, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Seismic gap, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Active fault, Elastic-rebound theory, 010502 geochemistry & geophysics, Fault scarp, Blind thrust earthquake, Strike-slip tectonics, 01 natural sciences, Geophysics, Fault trace, Space and Planetary Science, Geochemistry and Petrology, Interplate earthquake, Earth and Planetary Sciences (miscellaneous), [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: International audience; We analyse the Mw 7.7 Balochistan earthquake of 09/24/2013 based on ground surface deformation measured from sub-pixel correlation of Landsat-8 images, combined with back-projection and finite source modeling of teleseismic waveforms. The earthquake nucleated south of the Chaman strike-slip fault and propagated southwestward along the Hoshab fault at the front of the Kech Band. The rupture was mostly unilateral, propagated at 3 km/s on average and produced a 200 km surface fault trace with purely strike-slip displacement peaking to 10 m and averaging around 6 m. The finite source model shows that slip was maximum near the surface. Although the Hoshab fault is dipping by 45° to the North, in accordance with its origin as a thrust fault within the Makran accretionary prism, slip was nearly purely strike-slip during that earthquake. Large seismic slip on such a non-optimally oriented fault was enhanced possibly due to the influence of the free surface on dynamic stresses or to particular properties of the fault zone allowing for strong dynamic weakening. Strike-slip faulting on thrust fault within the eastern Makran is interpreted as due to eastward extrusion of the accretionary prism as it bulges out over the Indian plate. Portions of the Makran megathrust, some thrust faults in the Kirthar range and strike-slip faults within the Chaman fault system have been brought closer to failure by this earthquake. Aftershocks cluster within the Chaman fault system north of the epicenter, opposite to the direction of rupture propagation. By contrast, few aftershocks were detected in the area of maximum moment release. In this example, aftershocks cannot be used to infer earthquake characteristics.
Published: 2014
Full Text: View/download PDF

44. Injection tests at the EGS reservoir of Soultz-sous-Forêt. Seismic response of the GPK4 stimulations

Author: Michel Frogneux, Catherine Dorbath, Marco Calò, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)
Subjects: Soultz-sous-Forets, Induced seismicity, Double difference, Renewable Energy, Sustainability and the Environment, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Geology, Geotechnical Engineering and Engineering Geology, Enhanced geothermal system, Enhanced Geothermal System, Two stages, Seismology
Abstract: The European Enhanced Geothermal System (EGS) program of Soultz-sous-Forets is organized around three wells (GPK2, GPK3, and GPK4) drilled to a depth of about 5000 m. Hydraulic stimulations were performed in order to increase the injectivity of the reservoir and the connectivity among the wells. The stimulation of GPK4 was carried out in two stages, in September 2004 and in February 2005, followed by an acidification test performed in March 2005. The stimulations produced fewer induced events than those of the other wells, with interpretation remaining difficult. In this work we present some new observations on the seismicity of the GPK4 stimulations after a complete review of the seismic bulletins collected in 2004 and 2005. Furthermore, the events were relocated using the double difference method. The new images of the seismicity are presented in temporal sequences according to the main variations of the injection parameters. The seismic events that occurred during the 2004 stimulation are grouped in a dense cloud and centered on the well open-hole section, while in 2005 seismicity depicts a specific pattern suggesting that the “natural” stress field in the reservoir was not completely restored. Finally, the events recorded during the acidified test show that the reservoir behaved differently from the previous injections, which suggests that a different mechanism has controlled the induced seismicity.
Published: 2014
Full Text: View/download PDF

45. Automated identification, location, and volume estimation of rockfalls at Piton de la Fournaise volcano

Author: Diane Rivet, C. Baillard, Valérie Ferrazzini, Anne Mangeney, Claudio Satriano, Gilles Grandjean, Nikolai M. Shapiro, Clément Hibert, Patrice Boissier, Wayne C Crawford, Alessia Maggi, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Jacques-Louis Lions (LJLL (UMR_7598)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Ecole et Observatoire des sciences de la terre (EOST), Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Observatoire Volcanologique du Piton de la Fournaise (OVPF), Institut de Physique du Globe de Paris, Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ANR-08-RISK-0011,UNDERVOLC,Compréhension des processus volcaniques pour une meilleure prévention de l'aléa volcanique, application au volcan du Piton de la Fournaise, La Réunion.(2008), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), ANR_08_RISK_011/UnderVolc,ANR_08_RISK_011/UnderVolc, and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Volume estimation, 010502 geochemistry & geophysics, 01 natural sciences, Data set, Identification (information), Geophysics, Rockfall, Impact crater, Volcano, 13. Climate action, Long period, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Seismology, Fast marching method, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: International audience; Since the collapse of the Dolomieu crater floor at Piton de la Fournaise Volcano (la Réunion) in 2007, hundreds of seismic signals generated by rockfalls have been recorded daily at the Observatoire Volcanologique du Piton de la Fournaise (OVPF). To study rockfall activity over a long period of time, automated methods are required to process the available continuous seismic records. We present a set of automated methods designed to identify, locate, and estimate the volume of rockfalls from their seismic signals. The method used to automatically discriminate seismic signals generated by rockfalls from other common events recorded at OVPF is based on fuzzy sets and has a success rate of 92%. A kurtosis-based automated picking method makes it possible to precisely pick the onset time and the final time of the rockfall-generated seismic signals. We present methods to determine rockfall locations based on these accurate pickings and a surface-wave propagation model computed for each station using a Fast Marching Method. These methods have successfully located directly observed rockfalls with an accuracy of about 100 m. They also make it possible to compute the seismic energy generated by rockfalls, which is then used to retrieve their volume. The methods developed were applied to a data set of 12,422 rockfalls that occurred over a period extending from the collapse of the Dolomieu crater floor in April 2007 to the end of the UnderVolc project in May 2011 to identify the most hazardous areas of the Piton de la Fournaise volcano summit.
Published: 2014
Full Text: View/download PDF

46. Cross-borehole tomography with correlation delay times

Author: Christophe Zaroli, Guust Nolet, E. Diego Mercerat, ERA 6 Risque sismique (ERA 6 Risque sismique - Equipe recherche associée au LCPC), Avant création Cerema, Géoazur (GEOAZUR 7329), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])
Subjects: Diffraction, Physics, 010504 meteorology & atmospheric sciences, Scattering, Spectral element method, Borehole, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, Physics::Geophysics, Computational physics, Correlation, Geophysics, Geochemistry and Petrology, Time windows, Tomography, Seismogram, Seismology, 0105 earth and related environmental sciences
Abstract: International audience; We evaluated a comprehensive numerical experiment of finite-frequency tomography with ray-based ("banana-doughnut") kernels that tested all aspects of this method, starting from the generation of seismograms in a 3D model, the window selection, and the crosscorrelation with seismograms predicted for a background model, to the final regularized inversion. In particular, we tested if the quasilinearity of crosscorrelation delays allowed us to forego multiple (linearized) iterations in the case of strong reverberations characterizing multiple scattering and the gain in resolution that can be obtained by observing body-wave dispersion. Contrary to onset times, traveltimes observed by crosscorrelation allowed us to exploit energy arriving later in the time window centered in the P-wave or any other indentifiable ray arrival, either scattered from, or diffracted around, lateral heterogeneities. We tested using seismograms calculated by the spectral element method in a cross-borehole experiment conducted in a 3D checkerboard cube. The use of multiple frequency bands allowed us to estimate body-wave dispersion caused by diffraction effects. The large velocity contrast (10%) and the regularity of the checkerboard pattern caused severe reverberations that arrived late in the crosscorrelation windows. Nevertheless, the model resulting from the inversion with a data fit with reduced χ2red=1 resulted in an excellent correspondence with the input model and allowed for a complete validation of the linearizations that lay at the basis of the theory. The use of multiple frequencies led to a significant increase in resolution. Moreover, we evaluated a case in which the sign of the anomalies in the checkerboard was systematically reversed in the ray-theoretical solution, a clear demonstration of the reality of the "doughnut-hole" effect. The experiment validated finite-frequency theory and disqualified ray-theoretical inversions of crosscorrelation delay times. Read More: http://library.seg.org/doi/abs/10.1190/geo2013-0059.1
Published: 2013
Full Text: View/download PDF

47. Using centroid time-delays to characterize source durations and identify earthquakes with unique characteristics

Author: Victor C. Tsai, Zacharie Duputel, Hiroo Kanamori, Luis Rivera, Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Seismological Laboratory, California Institute of Technology (CALTECH), Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Time delays, Work (thermodynamics), 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Centroid, Transform fault, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 010502 geochemistry & geophysics, Geodesy, 01 natural sciences, Moment (mathematics), Stress (mechanics), Geophysics, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Seismic moment, Scaling, Geology, Seismology, 0105 earth and related environmental sciences
Abstract: International audience; The relationship between M0 and the rupture duration is often difficult to establish. This is particularly true for large earthquakes for which the moment rate functions (MRF) generally have complicated shapes, and the estimated durations can vary considerably depending on the methodology used to evaluate the MRF. In this work, we show that the centroid time-delay (τc) provides an alternative estimate of the source duration. Inverted MRFs often end gradually, making the end of coseismic rupture difficult to detect. In such cases, when the rupture duration is not well defined, the time-delay τc is a useful quantity to represent the first-order temporal characteristics of the rupture process. Variations in stress parameter Δσ can be investigated by assuming a standard scaling relationship between the seismic moment M0 and τc. This simple scaling relationship can also be used to identify unusual earthquakes, with unique source properties, such as events involving complicated rupture processes or earthquakes characterized by unusual rupture velocities, stress drops or aspect ratios.
Published: 2013
Full Text: View/download PDF

48. Seismic monitoring of soft-rock landslides: the Super-Sauze and Valoria case studies

Author: Alessandro Corsini, Jean-Philippe Malet, Manfred Joswig, Agnès Helmstetter, Alice Tonnellier, Jean Schmittbuhl, Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Dynamique globale et déformation active (IPGS) (IPGS-DGDA), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sismologie (IPGS) (IPGS-Sismologie), Dipartimento di Scienze della Terra [Modena], Università degli Studi di Modena e Reggio Emilia (UNIMORE), Institute of Geophysics, University of Stuttgart, Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Ecole et Observatoire des Sciences de la Terre (EOST), Institut National de l'Environnement Industriel et des Risques (INERIS), and Università degli Studi di Modena e Reggio Emilia = University of Modena and Reggio Emilia (UNIMORE)
Subjects: 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 010502 geochemistry & geophysics, 01 natural sciences, Rockfall, Image processing, Geochemistry and Petrology, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Early warning, geography, geography.geographical_feature_category, Microseism, Attenuation, Landslide, Mitigation of seismic motion, Geomorphology, Seismic signal, Seismic monitoring, Debris, Geophysics, Seismic array, Snowmelt, Geology, Seismology
Abstract: International audience; This work focuses on the characterization of seismic sources observed in clay-shale landslides. Two landslides are considered: Super-Sauze (France) and Valoria (Italy). The two landslides are developed in reworked clay-shales but differ in terms of dimensions and displacement rates. Thousands of seismic signals have been identified by a small seismic array in spite of the high-seismic attenuation of the material. Several detection methods are tested. A semi- automatic detection method is validated by the comparison with a manual detection. Seismic signals are classified in three groups based on the frequency content, the apparent velocity and the differentiation of P and S waves. It is supposed that the first group of seismic signals is associated to shearing or fracture events within the landslide bodies, while the second group may correspond to rockfalls or debris flows. A last group corresponds to external earthquakes. Seismic sources are located with an automatic beam-forming location method. Sources are clustered in several parts of the landslide in agreement with geomorphological observations. We found that the rate of rockfall and fracture events increases after periods of heavy rainfall or snowmelt. The rate of microseismicity and rockfall activity is also positively correlated with landslide displacement rates. External earthquakes did not influence the microseismic activity or the landslide movement, probably because the earthquake ground motion was too weak to trigger landslide events during the observation periods.
Published: 2013
Full Text: View/download PDF

49. Procedure to construct three-dimensional models of geothermal areas using seismic noise cross-correlations: application to the Soultz-sous-Forˆets enhanced geothermal site

Author: Xavier Kinnaert, Catherine Dorbath, Marco Calò, Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES), European Project, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Geothermal power, Seismic tomography, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Crustal structure, Seismic noise, 010502 geochemistry & geophysics, Enhanced geothermal system, 01 natural sciences, Geothermal exploration, Interferometry, Hydrothermal systems, Geophysics, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], Seismic array, Group velocity, Geothermal gradient, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: International audience; The aim of this work is to assess the feasibility of the noise-cross correlation tomography method for imaging and detecting potential geothermal reservoirs even in highly urbanised areas. We tested the noise correlation method to reconstruct the shape of the Soutlz-sous- Forˆets enhanced geothermal system (northern Alsace, France). We inverted Rayleigh waves (RWs) reconstructed from cross-correlations of 15 months of ambient seismic noise recorded by a seismic array installed around the Soutlz geothermal power plant. By correlating noise records between 22 receivers, we reconstructed RWs with sufficient signal-to-noise ratio for 231 interstation paths. The reconstructed waveforms were used to estimate group velocity dispersion curves at periods between 1.0 and 5.0 s. The results were inverted for 2-D group velocity maps, and finally for a 3-D S-wave velocity model from 0 to 5.2 km depth. Our results clearly show the presence of low velocity bodies in the crystalline basement below the Soultz power plant at depth of 4-5 km, and at shallower depth (2.5-3.5 km) beneath the Rittershoffen and Woerth villages. These observations, in agreement with some previous studies, confirm that our procedure is suitable for geothermal exploration. Furthermore, the model presented here provides some suggestions to improve the existing geothermal power plant and inferences for further explorations in the area.
Published: 2013
Full Text: View/download PDF

50. The long precursory phase of most large interplate earthquakes

Author: Virginie Durand, Hayrullah Karabulut, David Marsan, Michel Bouchon, Jean Schmittbuhl, Institut des Sciences de la Terre (ISTerre), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Mécanique des failles, Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Kandilli Observatory and Earthquake Research Institute (KOERI), Boǧaziçi üniversitesi = Boğaziçi University [Istanbul], Sismologie (IPGS) (IPGS-Sismologie), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Ecole et Observatoire des Sciences de la Terre (EOST), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Boğaziçi University [Istanbul], Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Remotely triggered earthquakes, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Structural geology, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Geophysics, Slip (materials science), tectonics and geodynamics, 010502 geochemistry & geophysics, Earthquake swarm, 01 natural sciences, Foreshock, Plate tectonics, Interplate earthquake, Intraplate earthquake, General Earth and Planetary Sciences, ComputingMilieux_MISCELLANEOUS, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: International audience; Many earthquakes are preceded by foreshocks. However, the mechanisms that generate foreshocks and the reason why they occur before some earthquakes and not others are unknown. Here we use seismic catalogues from the best instrumented areas of the North Pacific to analyse the foreshock sequences preceding all earthquakes there between 1999 and 2011, of magnitude larger than 6.5 and at depths shallower than 50 km. The data set comprises 31 earthquakes at plate boundaries, and 31 in plate interiors. We find that there is a remarkable contrast between the foreshock sequences of interplate compared with intraplate earthquakes. Most large earthquakes at plate interfaces in the North Pacific were preceded by accelerating seismic activity in the months to days leading up to the mainshock. In contrast, foreshocks are much less frequent in intraplate settings. We suggest that at plate boundaries, the interface between the two plates begins to slowly slip before the interface ruptures in a large earthquake. This relatively long precursory phase could help mitigate earthquake risk at plate boundaries.
Published: 2013
Full Text: View/download PDF

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Journal

Database

Publisher

68 results on '"Sismologie (IPGS)"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources