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1. Studies of a full-scale mechanical prototype line for the ANTARES neutrino telescope and tests of a prototype instrument for deep-sea acoustic measurements

Author

T. Legou, M. Ruppi, Chantal Compère, R. Ostasch, F. Urbano, Timo Karg, Diego Real, C. Gojak, V. Valente, G. Lamanna, V. Roca, V. Flaminio, C. Fiorello, I. Sokalski, J. Beltramelli, M. Taiuti, E. Kok, A. Rostovtsev, M.C. Bouwhuis, H. Loehner, A. Bigi, Chiara Roda, E. Falchini, Dominique Lefèvre, A. Le Van Suu, R. De Vita, F. Réthoré, V. Popa, H. Zaccone, J.R. Hubbard, Patrick Lamare, S. Cuneo, Julien Lavalle, Annarita Margiotta, K. Fratini, H. Laschinsky, Nicole Béthoux, R. Coniglione, Rosario Megna, C. Petta, L. Caponetto, C. Colnard, G. Wobbe, V. Niess, A. Ceres, Mario Musumeci, N. Randazzo, Thierry Pradier, G. Giacomelli, A. Heijboer, B. Vallage, B. Dinkespieler, J. Poinsignon, G. Damy, H. Le Provost, J. J. Aubert, R. Pillet, Nasser Kalantar-Nayestanaki, G. Vaudaine, G. Lelaizant, J.M. Gallone, F. Schmitt, F. Jouvenot, Paolo Sapienza, M. Jaquet, E. A. De Wolf, J. P. Schuller, G. Rusydi, Elie Aslanides, J. Carr, B. Hartmann, A. F. Yao, Holger Motz, A. Albert, P. Vernin, R. van Dantzig, R. Auer, S. Anvar, Juanan Aguilar, G. Wijnker, K. Salomon, M. de Jong, K. Streeb, Corinne Donzaud, J.J. Hernández-Rey, F. Salesa, J.-P. Pineau, D. Castel, G.V. Russo, S. Loucatos, M. Melissas, Robert Lahmann, Yvonne Becherini, Philippe Charvis, B. van Rens, J. P. Ernenwein, M. Marcelin, R. Masullo, Mohsen Harakeh, M. Circella, Alexander Kappes, F. Cafagna, L. A. M. Tasca, P. Valdy, D. Lo Presti, Gregory David Hallewell, Nathalie Palanque-Delabrouille, W. Kretschmer, V. Bertin, J. van Randwijk, Stephanie Escoffier, P. Payre, Tommaso Chiarusi, J.-L. Fuda, R. Blaes, M. Ageron, N. Cottini, G. Debonis, C. Kopper, V. Lyashuk, H. Peek, F. Lucarelli, S. Mangano, P. Lagier, J.D. Zornoza, M. Battaglieri, J.-X. Dessa, F. Fehr, G. Lim, Guillaume Lambard, Charling Tao, F.E. Ardellier-Desages, V. Rigaud, Jürgen Brunner, J.J. Destelle, E. Barbarito, U. F. Katz, C. Olivetto, S. Kuch, I. Dekeyser, L. Caillat, F. Guilloux, C. Naumann, Ana G. Pérez, F. Louis, P. Goret, C. De Marzo, Christian Tamburini, A. J. Noble, R. Bruijn, J. F. Drogou, T. Spona, F. Feinstein, J. Hößl, L. R. Sulak, M. Naumann-Godo, A. S. Cussatlegras, P. Piattelli, D. Zaborov, A. Kruijer, T. Montaruli, P. Chauchot, G. Loaec, J. Zúñiga, Anne Deschamps, S. Galeotti, Alain Mazure, J. Hogenbirk, Emanuele Castorina, C. Hoffman, G. Riccobene, D. Denans, F. Ameli, Vincenzo Cavasinni, C. Distefano, M. Billault, Y. Le Guen, M. Bazzotti, H. Kok, S. Basa, Eric Delagnes, J.-C. Languillat, M. Ripani, Jean-Francois Rolin, E. Carmona, Antoine Kouchner, G. Terreni, Dominique Durand, S. Cecchini, E. Heine, R. van Wijk, M. Morganti, Kay Graf, P. Coyle, Jean-Paul Kneib, Gisela Anton, T. Stolarczyk, C. Racca, J.-Y. Coail, Marc Régnier, S. Favard, A. Calzas, L. Moscoso, Rezo Shanidze, Antonio Capone, N. Girard, Maurizio Spurio, J. Roux, G. Venekamp, P. Kooijman, M. Jaspers, B. Verlaat, Yann Hello, P. Keller, G. van der Steenhoven, F. Mazéas, M. Anghinolfi, G. F. Burgio, J. Busto, P. Rewiersma, M. Mongelli, E. Migneco, F. Druillole, N. de Botton, High Energy Astrophys. & Astropart. Phys (API, FNWI), ANTARES (IHEF, IoP, FNWI), M. AGERON, J.A. AGUILAR, A. ALBERT, F. AMELI, M. ANGHINOLFI, G. ANTON, S. ANVAR, F. ARDELLIER-DESAGES, E. ASLANIDES, J-J. AUBERT, R. AUER, E. BARBARITO, S. BASA, M. BATTAGLIERI, M. BAZZOTTI, Y. BECHERINI, N. BETHOUX, J. BELTRAMELLI, V. BERTIN, A. BIGI, M. BILLAULT, R. BLAES, N. DE BOTTON, M.C. BOUWHUIS, R. BRUIJN, J. BRUNNER, G.F. BURGIO, J. BUSTO, F. CAFAGNA, L. CAILLAT, A. CALZAS, A. CAPONE, L. CAPONETTO, E. CARMONA, J. CARR, D. CASTEL, E. CASTORINA, V. CAVASINNI, S. CECCHINI, A. CERES, P. CHARVIS, P. CHAUCHOT, T. CHIARUSI, M. CIRCELLA, J-Y- COAIL, C. COLNARD, C. COMPERE, R. CONIGLIONE, N. COTTINI, P. COYLE, S. CUNEO, A-S. CUSSATLEGRAS, G. DAMY, R. VAN DANTZIG, G. DE BONIS, C. DE MARZO, R. DE VITA, I. DEKEYSER, E. DELAGNES, D. DENANS, A. DESCHAMPS, J.-X. DESSA, J-J. DESTELLE, B. DINKESPIELER, C. DISTEFANO, C. DONZAUD, J-F. DROGOU, F. DRUILLOLE, D. DURAND, J-P. ERNENWEIN, S. ESCOFFIER, E. FALCHINI, S. FAVARD, F. FEHR, F. FEINSTEIN, C. FIORELLO, V. FLAMINIO, K. FRATINI, J-L. FUDA, S. GALEOTTI, J-M. GALLONE, G. GIACOMELLI, N. GIRARD, C. GOJAK, PH. GORET, K. GRAF, G. HALLEWELL, M.N. HARAKEH, B. HARTMANN, A. HEIJBOER, E. HEINE, Y. HELLO, J.J. HERNANDEZ-REY, J. HOSSL, C. HOFFMAN, J. HOGENBIRK, J.R. HUBBARD, M. JAQUET, M. JASPERS, M. DE JONG, F. JOUVENOT, N. KALANTAR-NAYESTANAKI, A. KAPPES, T. KARG, U. KATZ, P. KELLER, J. P. KNEIB, E. KOK, H. KOK, P. KOOIJMAN, C. KOPPER, A. KOUCHNER, W. KRETSCHMER, A. KRUIJER, S. KUCH, P. LAGIER, R. LAHMANN, G. LAMANNA, P. LAMARE, G. LAMBARD, J-C. LANGUILLAT, H. LASCHINSKY, J. LAVALLE, Y. LE GUEN, H.LE PROVOST, A. LE VAN SUU, D. LEFEVRE, T. LEGOU, G. LELAIZANT, G. LIM, D.LO PRESTI, G. LOAEC, H. LOEHNER, S. LOUCATOS, F. LOUIS, F. LUCARELLI, V. LYASHUK, S. MANGANO, M. MARCELIN, A. MARGIOTTA, R. MASULLO, F. MAZEAS, A. MAZURE, R. MEGNA, M. MELISSAS, E. MIGNECO, M. MONGELLI, T. MONTARULI, M. MORGANTI, L. MOSCOSO, H. MOTZ, M. MUSUMECI, M. NAUMANN-GODO, C. NAUMANN, V. NIESS, T. NOBLE, C. OLIVETTO, R. OSTASCH, N. PALANQUE-DELABROUILLE, P. PAYRE, H. PEEK, A. PEREZ, C. PETTA, P. PIATTELLI, R. PILLET, J-P. PINEAU, J. POINSIGNON, V. POPA, T. PRADIER, C. RACCA, N. RANDAZZO, J. VAN RANDWIJK, D. REAL, M. REGNIER, B. VAN RENS, F. RETHORE, P. REWIERSMA, G. RICCOBENE, V. RIGAUD, M. RIPANI, V. ROCA, C. RODA, J.F. ROLIN, A. ROSTOVTSEV, J. ROUX, M. RUPPI, G.V. RUSSO, G. RUSYDI, F. SALESA, K. SALOMON, P. SAPIENZA, F. SCHMITT, J-P. SCHULLER, R. SHANIDZE, I. SOKALSKI, T. SPONA, M. SPURIO, G. VAN DER STEENHOVEN, T. STOLARCZYK, K. STREEB, L. SULAK, M. TAIUTI, C. TAMBURINI, C. TAO, L. TASCA, G. TERRENI, F. URBANO, P. VALDY, V. VALENTE, B. VALLAGE, G. VAUDAINE, G. VENEKAMP, B. VERLAAT, P. VERNIN, R. VAN WIJK, G. WIJNKER, G. WOBBE, E. DE WOLF, A-F. YAO, D. ZABOROV, H. ZACCONE, J.D. ZORNOZA, J. ZUNIGA, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), APC - Astrophysique des Hautes Energies (APC - AHE), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), ANTARES, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Aix Marseille Université (AMU), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] (UNIBO)-Università di Bologna [Bologna] (UNIBO), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), KVI - Center for Advanced Radiation Technology, and Research unit Nuclear & Hadron Physics

Subjects
leak detection, Nuclear and High Energy Physics, Acoustics, ELECTROMECHANICAL CABLES, Full scale, electromechanical cable, 01 natural sciences, Optics, Data acquisition, Data logger, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], optical time domain reflectometry, 14. Life underwater, Time domain, Electronics, sea deployment, 010306 general physics, Reflectometry, Instrumentation, Astroparticle physics, Physics, ANTARES, Hydrophone, antares, underwater neutrino telescope, 010308 nuclear & particles physics, business.industry, ANTARES, underwater neutrino telescope, leak detection, optical time domain reflectometry, electromechanical cable, sea deployment, UNDERWATER NEUTRINO TELESCOPES, 29.40.Ka, 29.90.+r, 92.10.Vz, business
Abstract

full-scale mechanical prototype line was deployed to a depth of 2500 m to test the leak tightness of the electronics containers and the pressure-resistant properties of an electromechanical cable under evaluation for use in the ANTARES deep-sea neutrino telescope. During a month-long immersion study, line parameter data were taken using miniature autonomous data loggers and shore-based optical time domain reflectometry. Details of the mechanical prototype line, the electromechanical cable and data acquisition are presented. Data taken during the immersion study revealed deficiencies in the pressure resistance of the electromechanical cable terminations at the entry points to the electronics containers. The improvements to the termination, which have been integrated into subsequent detection lines, are discussed. The line also allowed deep-sea acoustic measurements with a prototype hydrophone system. The technical setup of this system is described, and the first results of the data analysis are presented. (c) 2007 Elsevier B.V. All rights reserved.

Published
2007
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2. Steady late quaternary slip rate on the Cinarcik section of the North Anatolian fault near Istanbul, Turkey

Author

Christopher C. Sorlien, Marie-Helene Cormier, J.-X. Dessa, O. Atgin, Derman Dondurur, Helene Carton, Seda Okay, Günay Çifçi, H. Kurt, Emin Demirbağ, Leonardo Seeber, S. Gürçay, Michael S. Steckler, Donna J. Shillington, and Caner İmren

Subjects
010504 meteorology & atmospheric sciences, Istanbul turkey, North Anatolian Fault, Slip (materials science), Structural basin, 010502 geochemistry & geophysics, Strike-slip tectonics, 01 natural sciences, Geophysics, Multiple fault, General Earth and Planetary Sciences, Quaternary, Seismology, Geology, 0105 earth and related environmental sciences, Slip rate
Abstract

The distribution of plate motion between multiple fault strands and how this distribution may evolve remain poorly understood, despite the key implications for seismic hazards. The North Anatolian Fault in northwest Turkey is a prime example of a multistranded continental transform. Here we present the first constraints on late Quaternary slip rates on its northern branch across the Cinarcik Basin in the eastern Marmara Sea. We use both deep penetration and high-resolution multichannel seismic reflection data with a stratigraphic age model to show that a depocenter has persisted near the fault bend responsible for that transform basin. Successively older depocenters have been transported westward by fault motion relative to Eurasia, indicating a uniform right-lateral slip rate of 18.5 mm/yr over the last 500,000 years, compared to overall GPS rates (23-24 mm/yr). Thus, the northern branch has slipped at a nearly constant rate and has accounted for most of the relative plate motion between Eurasia and Anatolia since ~0.5 Ma.

Published
2013
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3. Frequency-Domain Full-Waveform Inversion of OBS Wide-Angle Seismic Data

Author

J. Virieux, S. Operto, J. X. Dessa, Géoazur (GEOAZUR 6526), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 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, 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), SEISCOPE, Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), and 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)

Subjects
Regional geology, Seismometer, 010504 meteorology & atmospheric sciences, Geophysical imaging, Engineering geology, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Inversion (meteorology), Gemology, 010502 geochemistry & geophysics, 01 natural sciences, Physics::Geophysics, Frequency domain, Economic geology, Seismology, Geology, 0105 earth and related environmental sciences
Abstract

International audience; In deep offshore, crustal-scale seismic imaging is classically performed by traveltime tomography applied to wide-angle seismic data recorded by a network of Ocean Bottom Seismometers (OBS). The resulting velocity model is of limited resolution. If the wide-angle experiment is multifold thanks to densely sampled OBSs, this large-scale velocity model can be used as a starting model for full-waveform inversion. Considering the full wavefield recorded over a broad range of apertures is expected to provide a significant resolution improvement in the velocity models. We applied 2D frequency-domain full-waveform inversion to wide-angle data recorded by 100 OBSs deployed perpendicular to the trench axis of a subduction zone, offshore Japan. The full-waveform modelling/inversion are entirely implemented in the frequency domain. Thirteen frequencies ranging from 3 to 15 Hz were inverted sequentially with a weighted least-square method, the velocity model obtained for each frequency being used to start the inversion of the next one. The resolution of the velocity models inferred from traveltime and full waveform tomographies were estimated to be ~10 km and 500 m respectively at 10 km depth suggesting a resolution improvement by an over order of magnitude. The relevance of the structures was assessed by ray tracing and full-waveform modelling.

Published
2006
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4. Infrasound modeling in a spherical heterogeneous atmosphere

Author

Jean Virieux, S. Lambotte, and J.-X. Dessa

Subjects
Physics, 010504 meteorology & atmospheric sciences, business.industry, Infrasound, Paraxial approximation, Spherical coordinate system, Figure of the Earth, Acoustic wave, 010502 geochemistry & geophysics, Curvature, 01 natural sciences, Computational physics, Ray tracing (physics), Geophysics, Amplitude, Optics, General Earth and Planetary Sciences, business, 0105 earth and related environmental sciences
Abstract

The deployment of a worldwide network for infrasound detection requires numerical methods for modeling these signals over long distances. A ray theoretical approach appears robust and efficient. It furthermore allows a straightforward interpretation of recorded phases. We have developed a three-dimensional Hamiltonian ray tracing for modeling linear acoustic waves in the atmosphere. Propagating over distances superior to 500 km requires the curvature of the Earth to be considered, which is achieved by using spherical coordinates. High atmospheric winds are properly handled through a modified Hamiltonian. These winds as well as sound velocity can change significantly during long-lasting propagations; these variations are also included in our modeling. Finally, the amplitude of infrasonic signals is computed by concomitantly solving for paraxial rays and assessing the evolution of the ray tube thus defined. We present the theory for this atmospheric infrasound modeling and some simple applications that establish its robustness and potential.

Published
2005
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5. Infrasound monitoring of volcanoes to probe high-altitude winds

Author

M. Lardy, Sylvie Vergniolle, S. Lambotte, Philipson Bani, J.-X. Dessa, Elisabeth Blanc, A. Le Pichon, Douglas P. Drob, 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), E. O. Hulburt Center for Space Research, Naval Research Laboratory (NRL), 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), Laboratoire de Géosciences Marines (LGM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie]), Institut de Physique du Globe de Paris (IPGP), 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 Pierre et Marie Curie - Paris 6 (UPMC)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), 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
Atmospheric Science, 010504 meteorology & atmospheric sciences, Infrasound, Soil Science, Aquatic Science, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Wind speed, Geochemistry and Petrology, Trend surface analysis, Earth and Planetary Sciences (miscellaneous), Stratosphere, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, geography, geography.geographical_feature_category, Ecology, Paleontology, Forestry, Effects of high altitude on humans, Azimuth, Geophysics, Amplitude, Volcano, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Climatology, Geology
Abstract

International audience; Active volcanoes in the Vanuatu archipelago permanently generate infrasonic waves. Their monitoring over 1 year exhibits clear seasonal trends in the direction of arrival of the detected signals. From summer to winter the azimuth variation reaches 15°. This deviation is essentially due to the reversibility of the zonal stratospheric wind with season which strongly affects the deflection of the ray direction. A three-dimensional (3-D) ray-tracing modeling roughly explains the observed seasonal trend in the azimuth variation but underestimates its amplitude. The discrepancy between the measurements and the results of simulation is explained by undervalued wind speeds in the upper atmosphere. Infrasonic observations are used as input of an inversion scheme for adjusting the vertical structure of the wind in the upper stratosphere and mesosphere. It is shown that the mesospheric zonal winds are underestimated by at least 20 m/s throughout the year with differences reaching 50 m/s.

Published
2005
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6. Deep seismic imaging of the eastern Nankai trough, Japan, from multifold ocean bottom seismometer data by combined travel time tomography and prestack depth migration

Author

G. Pascal, Yoshiyuki Kaneda, Kohichi Uhira, J. X. Dessa, Stéphane Operto, Ayako Nakanishi, and Shuichi Kodaira

Subjects
Seismometer, Seismic gap, Atmospheric Science, Accretionary wedge, 010504 meteorology & atmospheric sciences, Geophysical imaging, Trough (geology), Soil Science, Aquatic Science, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Ecology, Subduction, Paleontology, Forestry, Collision zone, Tectonics, Geophysics, Space and Planetary Science, Geology, Seismology
Abstract

[1] The easternmost segment of the Nankai trough remained unruptured during the 1944 and 1946 earthquakes that affected the rest of the trench. It is therefore a zone of seismic gap that also undergoes a peculiar tectonic regime due to its proximity with the Izu collision zone. We investigate this area with densely sampled active seismic data. One hundred ocean bottom seismometers, spaced only 1 km apart, were deployed along a line perpendicular to the trough. A two-step tomographic approach, designed for this type of acquisition, is applied: first, a long-wavelength velocity model is built by a linearized inversion of first arrival travel times, its resolution is assessed, and its reliability is confirmed through a semiglobal approach in which a large range of starting models is tested; second, this tomographic model is used to exploit late reflected arrivals with a prestack depth migration, the result of which is validated by classically modeling refraction and reflection travel times in the derived structural model. Thus both velocities and discontinuities are mapped in our model with a minimum of data interpretation and a priori knowledge. Our results bring new insights on the deep crustal zones of the margin and its evolution. The existence of presently inactivated major thrusts is very clearly evidenced in the backstop. A general timing for its evolution and deformation is proposed. Farther seaward, the presence of a subducted ridge beneath the accretionary wedge is confirmed. Its compressive structure and origin are demonstrated. It exhibits a thickened lower crust which nature is discussed. Besides, strong analogies between this “Paleo-Zenisu” subducting ridge and the Zenisu ridge, observed farther south, are also emphasized, bringing evidences for a steady state crustal deformation pattern.

Published
2004
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7. Multiscale seismic imaging of the eastern Nankai trough by full waveform inversion

Author

Ayako Nakanishi, Shuichi Kodaira, Stéphane Operto, G. Pascal, Jean Virieux, J. X. Dessa, Yoshiyuki Kaneda, Géoazur (GEOAZUR 6526), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 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, 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), SEISCOPE, Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), and 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)

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Exploration geophysics, Subduction, Marine geology, Crust, Geophysics, Sedimentary basin, 010502 geochemistry & geophysics, 01 natural sciences, Tectonics, [SDU]Sciences of the Universe [physics], 13. Climate action, Tectonophysics, General Earth and Planetary Sciences, 14. Life underwater, Structural geology, Geology, Seismology, 0105 earth and related environmental sciences
Abstract

[1] Classical active seismic methods fail to sharply image the earth’s deep crust. We present the first crustal-scale application of 2-D full waveform inversion based on dense ocean bottom seismic data to investigate the Eastern Nankai subduction system (Japan). This approach allows to quantify seismic velocities up to an unprecedented degree of resolution. Results reveal compressive tectonic features within both the subducting oceanic crust and the backstop. At depth, velocity anomalies along major faults and structural discontinuities bring evidence for the presence of fluids and weakened material and also for a possible coseismic slip partitioning structure. INDEX TERMS: 0902 Exploration Geophysics: Computational methods, seismic; 3025 Marine Geology and Geophysics: Marine seismics (0935); 8010 Structural Geology: Fractures and faults; 8105 Tectonophysics: Continental margins and sedimentary basins (1212). Citation: Dessa, J.-X., S. Operto, S. Kodaira, A. Nakanishi, G. Pascal, J. Virieux, and Y. Kaneda (2004), Multiscale seismic imaging of the eastern Nankai trough by full waveform inversion, Geophys. Res. Lett., 31, L18606, doi:10.1029/2004GL020453.

Published
2004
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8. Paraxial ray tracing for atmospheric wave propagation

Author

J.-X. Dessa, Jean Virieux, Nicolas Garnier, Elisabeth Blanc, 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), 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
Physics, 010504 meteorology & atmospheric sciences, Wave propagation, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Atmospheric wave, Paraxial approximation, Acoustic wave, Tracing, 010502 geochemistry & geophysics, 01 natural sciences, Ray, Wind speed, Computational physics, Ray tracing (physics), Geophysics, Optics, 13. Climate action, [SDU]Sciences of the Universe [physics], General Earth and Planetary Sciences, business, 0105 earth and related environmental sciences
Abstract

[1] Ray tracing for sonic wave propagation in a two-dimensional atmosphere structure is performed in the presence of spatially variable wind by using an Hamiltonian approach. Paraxial ray tracing is deduced by first-order perturbations. Using standard atmospheric data or illustrative models, we test numerically the Hamiltonian approach. The ray tracing allows accurate estimation of trajectories and associated travel-times as well as stable and accurate amplitude variations along a ray. Lateral variations of both sonic and wind velocity are important for quantitative evaluation of acoustic waves. Gradients of the wind field must be taken into account for precise quantification of ray trajectories and, consequently, for the localization of ground impacts, a key element for any micro-barometric recording station.

Published
2004
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9. Infrasonic imaging of the Kunlun Mountains for the great 2001 China earthquake

Author

Martin Vallée, J. X. Dessa, J. Guilbert, M. Ulziibat, and A. Le Pichon

Subjects
geography, Plateau, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Infrasound, 010502 geochemistry & geophysics, 01 natural sciences, Pressure field, Displacement (vector), Atmosphere, Geophysics, 13. Climate action, Epicenter, General Earth and Planetary Sciences, Far East, China, Geology, Seismology, 0105 earth and related environmental sciences
Abstract

[1] On November 14, 2001, a strong earthquake occurred on the high plateau of western China. At a distance of 1800 km from the epicenter, coherent infrasonic waves were detected for more than one hour. Using both an inverse location procedure and a complete simulation of the radiated pressure field, distant source regions are accurately located. The seismo-acoustic coupling along a mountain belt is clearly demonstrated. Such an event offers an opportunity to validate velocity models in the atmosphere as well as to improve the understanding of the amplification of ground displacement caused by the topography.

Published
2003
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