Search

SUMMARY On the 9th of January 2020, an Mw 6.4 strike-slip earthquake took place north of the Asian margin of the Bering Sea. The earthquake occurred within the known reverse-right-lateral active fault zone, called Khatyrka–Vyvenka, which transverses the Koryak Highland from SE to NW and is thought to be a surface manifestation of the Asian portion of either the Bering plate boundary or the northern edge of the Alaskan stream. No other strong earthquake has ever been recorded in this remote uninhabited area and the few existing seismic stations provide poor quality earthquake locations. We adopt SAR interferometry (InSAR) technique to define an improved location of the Koryak 2020 earthquake and constrain the seismic source. The analysis of the 2020 event revealed a previously unknown active fault of left-lateral kinematics that is possibly hidden and strikes NW transversely to the Khatyrka–Vyvenka fault zone. Although several mechanisms could account for left-lateral kinematics of this fault, we propose that the structure is part of a more extended NW fault structure, that formed in pre-neotectonic times and has played a role of a pre-existing rheological discontinuity. This revived NW structure together with a similar structure located easterly, so far aseismic, make the plate/stream boundary segmented, step-like in plan view. The step-like boundary geometry may be the result of internal transform deformation of a rigid plate, but it is better explained by deflections of the Alaskan stream edge at local crustal asperities, which are pre-Cenozoic terrains.

In this work we present a processing chain we implemented to calculate, in a completely automatic way, the seismic source with distributed slip starting from the Differential Synthetic Aperture Radar Interferometry (DInSAR) coseismic displacement maps generated through the EPOSAR service.EPOSAR is a scientific service of EPOS (European Plate Observing System) Research Infrastructure, developed by CNR-IREA, that provides coseismic displacement maps at global scale. In particular, following the occurrence of an earthquake of a) magnitude greater and b) depth smaller than selected thresholds, EPOSAR automatically retrieves and process all the Copernicus Sentinel-1 data necessary to generate all the possible DInSAR coseismic maps within a monthly time window, so that the earthquake can be analyzed from different satellite paths. We further remark that the EPOSAR service is currently operative and the generated DInSAR products are freely available to the scientific community through the EPOS infrastructure.In this work we present the implementation of an automatic new modeling chain, by acting in cascade to the EPOSAR service, with a twofold aim: revealing the seismic source at the occurrence of every new event detectable through DInSAR and providing a complete database of sources that includes all the earthquakes occurred since the launch of Sentinel-1 satellites.The procedure starts from DInSAR data, produced by the EPOSAR service, and a focal mechanism automatically retrieved from several catalogs (USGS, Global CMT, INGV-TDMT). The non-linear inversion is implemented with two stages, coarse and refined, to get a robust and well centered, uniform slip solution; this source is then extended and subdivided into small elements to get the slip distribution via linear inversion. For every single step, a number of algorithms, based on two decades of experience in modeling at INGV, were implemented to face the large number of options and conditions usually handled by an expert user: image selection, setup and iterative update of the input parameters, definition of the regularization strength, detection of specific conditions (point-source, poorly constraining data, etc.). The model is also automatically updated with the availability of new DInSAR data, always balancing the contribution from ascending and descending acquisitions.The developed tool is designed to deploy a service aimed at providing a quick and reliable automatic fault model solution and it has been tested and validated on hundred up to date events, characterized by different magnitudes, rupture mechanisms and locations. In this work, we present the main algorithm aspects and performances, addressing also the potentialities arising with the availability of a complete and homogeneous database of DInSAR-based source models: definition of updated scaling factors, systematic bias, etc.We finally remark that our tool will be soon operative and integrated within the EPOS infrastructure, thus allowing the user community to access the generated results and benefit from quick and reliable products on the source mechanisms of the more significant seismic events.

Differential Synthetic Aperture Radar Interferometry (DInSAR) is a key method to estimate, with centimeter accuracy, the earth surface displacements caused by natural events or anthropogenic activities. Furthermore, since 2014 the scientific community can benefit from the huge spaceborne SAR data archives acquired by the Copernicus Sentinel-1 (S1) satellite constellation, which operationally provides SAR data with a free and open data access policy at nearly global scale. By using the S1 acquisitions, an automatic and unsupervised processing tool that generates co-seismic interferograms and LOS displacement maps has been developed. This tool routinely queries two different earthquake catalogs (USGS and INGV) to trigger, in automatic way, the S1 data download and the DInSAR processing through the Parallel Small BAseline Subsets (P-SBAS) algorithm. In particular, in order to guide the algorithm to only intercept the earthquakes which may produce ground displacements detectable through the DInSAR technology, the tool starts the SAR data processing for those events with a magnitude greater than 4.0 in Europe, and greater than 5.5 at a global scale.We first remark that, in order to optimize the extension of the investigated area, thus reducing the processing time and effectively exploiting the available computing resources, an algorithm for the estimation of the co-seismically affected area has been integrated as first step of the workflow. More specifically, by considering the moment tensors provided by public catalogs (USGS, INGV, Global CMT project), a forward modelling procedure generates the predicted co-seismic displacement field, used by the P-SBAS algorithm to optimize some of the DInSAR processing steps. In particular, the phase unwrapping (PhU) algorithm is applied only to the part of the DInSAR interferograms delimited by the area identified through the predicted scenario and not to the whole S1 scene. In addition, the presented automatic and unsupervised tool has been migrated within a Cloud Computing (CC) environment, specifically the Amazon Web Service (AWS). This strategy allows us a more efficient management of the needed computing resources also in emergency scenario. The adopted solutions allowed the creation of a worldwide co-seismic maps database. Indeed, by benefiting of the last seven years of Sentinel-1 operation, the tool has generated approximately 6500 interferograms and LOS displacement maps, corresponding to a total of 383 investigated earthquakes. Note also that the generated interferograms and displacement maps have been made available for the scientific community through the EPOS infrastructure and the Geohazards Exploitation Platform, thus helping scientists and researchers to investigate the dynamics of surface deformation in the seismic zones around the Earth also in the case they have not available specific DInSAR processing capabilities and/or skills.

We investigate a large geodetic data set of interferometric synthetic aperture radar (InSAR) and GPS measurements to determine the source parameters for the three main shocks of the 2016 Central Italy earthquake sequence on 24 August and 26 and 30 October (Mw 6.1, 5.9, and 6.5, respectively). Our preferred model is consistent with the activation of four main coseismic asperities belonging to the SW dipping normal fault system associated with the Mount Gorzano-Mount Vettore-Mount Bove alignment. Additional slip, equivalent to a Mw ~ 6.1–6.2 earthquake, on a secondary (1) NE dipping antithetic fault and/or (2) on a WNW dipping low-angle fault in the hanging wall of the main system is required to better reproduce the complex deformation pattern associated with the greatest seismic event (the Mw 6.5 earthquake). The recognition of ancillary faults involved in the sequence suggests a complex interaction in the activated crustal volume between the main normal faults and the secondary structures and a partitioning of strain release.

The present study analyzes the sequence of 4 important earthquakes occurred in Mexico from September 2017 to February 2018, exploiting the large availability of InSAR data and analytical models, with a twofold goal: to privede new solutions for seismogenic sources, completely independent from seismological data, and to discuss methodological aspects related to the non-linear and linear inverse problem. We review and update an earlier study, focused on the concept of resolution, showing the level of detail achievable in the investigation of the slip distribution based on geodetic observations, according to data availability, fault locations and event magnitudes. We further give new insights into the relationship between fault resolution and parameter uncertainty, demonstrating that a realistic assessment is strictly related to a proper fault subdivision. We eventually discourage the use of qualitative approaches, such as the checkerboard test, to evaluate the data resolving power and suggest the adoption of quantitative indicators, like the Dirichlet Spread Function, normalized, easy to calculate and mathematically robust.

Sinkholes commonly form by subsurface dissolution cavities that collapse after the overlying layers become mechanically unsupported. Sinkholes along the Dead Sea shorelines are preceded by, associated with, and followed by gradual surface subsidence that accompanies the cavities' growth. We exploit satellite radar interferometry (interferometric synthetic aperture radar) to resolve temporal and spatial relationships between gradual subsidence and sinkhole collapse. The geometry of the deflating cavity roof is determined by elastic inverse modeling of the surface displacements. A Coulomb failure stress criterion is applied to calculate the stress field induced by the deflating cavity at the ground surface. We find that the induced stress field favors generation of sinkholes at the perimeters of the subsiding areas rather than at their centers, in agreement with field observations, providing important information for sinkhole hazard assessment. Further, our analysis suggests that short-term deformation in consolidated gravel layers at shallow depths could be approximated by simple elastic modeling.

Online Material: Tables of moment tensor elements; SAR image pairs and coseismic displacement gradients; figures of InSAR data, model parameter tradeoffs, and observed and modeled displacements. On 26 January 2014 at 13:55 UTC, an M w 6.0 earthquake struck the island of Cephalonia, Greece, followed five hours later by an M w 5.3 aftershock and by an M w 5.9 event on 3 February 2014 at 03:08 UTC (National Observatory of Athens, Institute of Geodynamics [NOA‐GI]). The epicenter of the M w 6.0 event was relocated 2 km east of the town of Lixouri, and that of the M w 5.9 event at the tip of the Gulf of Argostoli, in the northern part of the Paliki peninsula (Fig. 1; Karastathis et al. , 2014; Papadopoulos et al. , 2014). Extensive structural damage and widespread environmental effects were induced throughout the Paliki peninsula and along the eastern coast of the Gulf of Argostoli (Valkaniotis et al. , 2014). Quays, sidewalks, and piers were damaged in the waterfront areas of the towns of Lixouri and Argostoli, the island capital, and liquefactions, road failures, rock falls, and small landslides were observed. Most of the latter effects took place in the aftermath of the 26 January 2014 event and were reactivated one week later by the 3 February earthquake. Figure 1. Location map showing the tectonic context of the Aegean Sea and the main faults on the island of Cephalonia. Colored rectangles and magenta triangles indicate the Synthetic Aperture Radar (SAR) frame coverage and the continuous Global Positioning System (cGPS) stations, respectively. Yellow stars indicate the relocated epicenters of the three largest events of the 2014 sequence (Karastathis et al. , 2014). Diverging and converging arrows in the top‐right map indicate approximate horizontal projections of the P axis (compression) and T axis (extension), respectively, based on figure 5b in …

Online Material: Additional figures and tables. On 20 May 2012, an M L 5.9 earthquake (Table 1) occurred near the town of Finale Emilia, in the central Po plain, Northern Italy (Fig. 1a). The mainshock caused seven casualties and the collapse of several historical buildings and industrial sheds. The earthquake sequence continued with diminishing aftershock magnitudes until 29 May, when an M L 5.8 earthquake occurred near the town of Mirandola, ∼12 km west‐southwest of the mainshock (Scognamiglio et al. , 2012). This second mainshock started a new aftershock sequence in this area, and increased structural damage and collapses, causing 19 more casualties and increasing to 15,000 the number of evacuees. View this table: Table 1 Largest Earthquakes ( M L>5) of the 2012 Emilia Seismic Sequence (http://iside.rm.ingv.it) Figure 1. (a) Geostructural setting of the Emilia 2012 seismic sequence area showing the vertically projected top traces of the main thrust fault planes, and the anticlinal axes, modified after (Bigi et al. , 1983; Boccaletti et al. , 2010; Picotti and Pazzaglia, 2008); white dots, aftershock epicenters. Large instrumental and historical earthquakes are also shown (http://iside.rm.ingv.it, last accessed April 2013); Rovida et al. , 2011); yellow rectangles, footprint of the COSMO‐SkyMed (CSK) and Radarsat satellite image pairs. The focal mechanisms of the two main events (from Malagnini et al. , 2012) are reported in the map. (b) Geological profiles interpreted from seismic reflection data after (Boccaletti et al. , 2010) corresponding to traces A and B in (a). Shortly after the first mainshock, the Department of Civil Protection (DPC) activated the Italian Space Agency (ASI), which provided post‐seismic Synthetic Aperture Radar (SAR) Interferometry data coverage with all four Constellation of Small Satellites for the Mediterranean Basin Observation (COSMO‐SkyMed) SAR satellites. Within the next two weeks, several SAR Interferometry (InSAR) image pairs were processed by the Istituto Nazionale di Geofisica e Vulcanologia–Space‐based Monitoring System …

Several independent indicators imply a high probability of a great ( M > 8) earthquake rupture of the subduction megathrust under the Mentawai Islands of West Sumatra. The human consequences of such an event depend crucially on its tsunamigenic potential, which in turn depends on unpredictable details of slip distribution on the megathrust and how resulting seafloor movements and the propagating tsunami waves interact with bathymetry. Here we address the forward problem by modelling about 1000 possible complex earthquake ruptures and calculating the seafloor displacements and tsunami wave height distributions that would result from the most likely 100 or so, as judged by reference to paleogeodetic data. Additionally we carry out a systematic study of the importance of the location of maximum slip with respect to the morphology of the fore-arc complex. Our results indicate a generally smaller regional tsunami hazard than was realised in Aceh during the December 2004 event, though more than 20% of simulations result in tsunami wave heights of more than 5 m for the southern Sumatran cities of Padang and Bengkulu. The extreme events in these simulations produce results which are consistent with recent deterministic studies. The study confirms the sensitivity of predicted wave heights to the distribution of slip even for events with similar moment and reproduces Plafker's rule of thumb. Additionally we show that the maximum wave height observed at a single location scales with the magnitude though data for all magnitudes exhibit extreme variability. Finally, we show that for any coastal location in the near field of the earthquake, despite the complexity of the earthquake rupture simulations and the large range of magnitudes modelled, the timing of inundation is constant to first order and the maximum height of the modelled waves is directly proportional to the vertical coseismic displacement experienced at that point. These results may assist in developing tsunami preparedness strategies around the Indian Ocean and in particular along the coasts of western Sumatra.

SUMMARY We model the time histories of coseismic stress changes produced by an earthquake rupture on an extended fault in a layered elastic half-space. We compute the stress perturbations caused by earthquakes using the discrete wavenumber and the reflectivity methods. We investigate the influence on the computed Coulomb stress changes of the adopted crustal velocity model, the rupture history and slip duration as well as the poro-elastic model assumed to calculate the pore-pressure changes. The comparison between the spatio-temporal evolution of the induced stress field, calculated for different crustal models and rupture histories, allows us to assess the depth and frequency dependence of the induced stress perturbation and the relative weight of dynamic and static stress changes. Our results show that the rise time and the rupture directivity are more important for characterizing the simulated stress time histories than the details of the rupture history. The adopted poro-elastic model affects the static stress changes more than the transient stress perturbations. The results of this study should be taken into account to model fault interaction through elastic stress transfer.

Olivieri, M.; Spada, G.; Antonioli, A., and Galassi, G., 2015. Mazara del Vallo tide gauge observations (1906–16): Land subsidence or sea-level rise? Tide gauge (TG) data constitute an invaluable tool for the interpretation of short- and long-term sea-level changes occurring in the Mediterranean Sea. The complex geophysical environment and the limited amount of sufficiently long records make the interpretation of local signals problematic because these are often affected by interlacing processes. Starting from newly disclosed TG records from the site of Mazara del Vallo (SW Sicily), we analyze simultaneously the time series available from other locations in Sicily across the beginning of the 20th century (Messina and Palermo). Despite the limited record length, we show that these observations provide new perspectives on the causes of the observed sea-level variations in the central Mediterranean region, and, in particular, they challenge previous tenets regarding the extent of land movements caus...

In this study we use Synthetic Aperture Radar Differential Interferometry (DInSAR) and seismological data to constrain the source of the mainshock of the 2013 Lunigiana (North-western Italy) seismic sequence, namely an Mw 5.1 event occurred on 2013 June 21. The sequence took place in a transfer zone located between the Lunigiana (North) and Garfagnana (South) graben. As the destructive Mw 6.2 earthquake occurred in 1920 has demonstrated, this area is seismically active and is considered the most hazardous area of the Northern Apennines. Hypocentre relocations of the Lunigiana sequence aftershocks are well fitted by a ~ 45° N-dipping fault plane, whereas the focal mechanism solution yields a dip-slip mechanism with a slight right-lateral strike-slip component. Surface displacements estimated from ascending COSMO-SkyMed imagery acquired in the time-span of a single day around the mainshock were used to derive an elastic dislocation model. The estimated slip distributions computed on fixed and variable size meshes show peak values of 30 cm and 40 cm respectively. Static stress variation analysis was performed to analyze possible stress overloads on the closest seismogenic sources. Our results provide insight into the tectonics of the Northern Apennines, suggesting the fundamental role of transfer fault zones in intra-mountain basin origin and in the assessment of seismic hazard in an extensional tectonic regime.

SUMMARY A comparison is performed between predictions of coseismic and post-seismic deformations, based on two diVerent earth models. The main purpose of this work is to clarify in a rigorous manner the role of sphericity in the assessment of both residual deformations and large-scale post-seismic motions. The two models considered in this study are commonly employed for predictions of post-seismic deformations. They exhibit the common feature of a layered viscoelastic structure but diVer in their global geometrical features, the first being characterized by a flat-earth approximation and the second by a spherical geometry. The purpose of this study is twofold. First, we wish to assess the influence of sphericity in predictions of post-seismic deformations, especially in the far field of major earthquakes. Second, we wish to elucidate the potential role of stress migration in earthquake triggering over great distances.

Stepper motor drives exhibit advantages like open loop capability, high torque density and lower cost with respect to other brushless servo alternatives. However, the typical performances of conventional open loop stepper motor drives are limited, making them unsuitable where high speeds, fast dynamics and smooth motion is required. They are also easily prone to stall and usually produce loud audible noise. Recently, the increasing price of rare earth materials used in permanent magnets is making the use of high-quality PMSMs prohibitive when medium requirements are present. To achieve performances comparable to those of a servo drive, vector control is applied, since the hybrid stepper motor can be considered as a special case of the PMSM, characterized by the presence of two phases and a high pole count (usually 50 pole pairs). Removal of the position/speed sensor is therefore highly desirable to maintain low system costs. In this paper sensorless speed control is achieved by means of a simple yet reliable stationary reference frame back-EMF observer, that can be analytically tuned. The adoption of a standard three phase inverter contributes to the reduction of the system costs, while the injection of a small constant direct axis current leads to a strong reduction of the estimation noise effect, especially at low speed. Both a laboratory test bench and an actual industrial automation machine (i.e. high speed labeller) are considered for experiments, demonstrating the importance and effectiveness of the proposal.

[1] We define the geometric and kinematic characteristics of the fault activated during the Mw = 6.3, 6 April 2009 L'Aquila earthquake, from the modeling of Envisat and COSMO-SkyMed (the first ever X-band interferogram inverted for a coseismic dislocation study) DInSAR interferograms. Our best-fit solution for the main shock is represented by a normal fault ∼16 km long and ∼12 km wide, with a small right-lateral component, dipping 47°SW with a maximum slip of ∼90 cm. Although the seismic dislocation probably ended at 1 km depth, the updip projection of the fault plane corresponds to the northern segment of the mapped Paganica–S. Demetrio fault, where alignment of surface breaks was observed in the field. The absence of this fault in existing seismic source catalogues suggests that an improved approach, involving detailed surface and subsurface geological and geophysical investigations, is needed for a better assessment of the seismic hazard at the local scale.

We investigate controls on tsunami generation and propagation in the near-field of great megathrust earthquakes using a series of numerical simulations of subduction and tsunamigenesis on the Sumatran forearc. The Sunda megathrust here is advanced in its seismic cycle and may be ready for another great earthquake. We calculate the seafloor displacements and tsunami wave heights for about 100 complex earthquake ruptures whose synthesis was informed by reference to geodetic and stress accumulation studies. Remarkably, results show that, for any near-field location: (1) the timing of tsunami inundation is independent of slipdistribution on the earthquake or even of its magnitude, and (2) the maximum wave height is directly proportional to the vertical coseismic displacement experienced at that location. Both observations are explained by the dominance of long wavelength crustal flexure in near-field tsunamigenesis. The results show, for the first time, that a single estimate of vertical coseismic displacement might provide a reliable short-term forecast of the maximum height of tsunami waves. Published version

[1] We analyze the coseismic stress perturbation during the 17 June 2000 south Iceland seismic sequence; the main shock (Ms 6.6) was followed by three large events within a few tens of seconds (8, 26, and 30 s) located within 80 km. The aim of this paper is to investigate short-term fault interaction and instantaneous triggering. This happens when a fault perturbed by a stress change fails before the end of the transient stress perturbation. We compute the shear, normal, and Coulomb stress changes as functions of time in a stratified elastic half-space by using discrete wave number and reflectivity methods. We calculate dynamic stresses caused by the main shock at the hypocenters of these three subsequent events. Our numerical results show that the onset of the last two events is slightly delayed with respect to the arrival time of the second positive peak of Coulomb stress variation, while the first event occurred after the first positive stress peak. We have also analyzed the response of a spring slider system representing a fault governed by a rate- and state-dependent friction law, perturbed by shear and normal stress variations caused by the main shock. The fault response to the computed stress perturbations is always clock advanced. We have found suitable constitutive parameters of the modeled fault that allow the instantaneous dynamic triggering of these three earthquakes. If the initial sliding velocity is comparable with the tectonic loading velocity, we obtained failure times close to the observed origin times for low values of the initial effective normal stress.

We investigate the coseismic stress redistribution during the 25 March 1998 great Antarctic plate (MW 8.1) earthquake, in which the mainshock consisted of two distinct subevents separated in time by several tens of seconds. We compute the dynamic stress time histories for the fault geometry and the rupture and slip history determined by Henry et al. (2000), using the discrete wavenumber and re- flectivity method of Cotton and Coutant (1997), both for a homogeneous and a strat- ified half-space. We first image the coseismic stress evolution caused by the first subevent on the fault plane of the second one for both the velocity models. We compute both shear and normal stress changes and a time-dependent Coulomb failure function (CFF). Our results show that the shear stress changes have larger amplitudes than the other stress components and hence are the primary control on the evolution of the CFF. The dynamic stress amplitudes are larger than the static stress pertur- bations, with the largest positive dynamic stress peak on the second subevent fault plane reaching slightly less than 0.2 MPa at 60 sec and 65 sec after the nucleation, for the layered and the homogeneous crustal models, respectively. We suggest that the dynamic stress changes caused by the first subevent promoted a nearly instan- taneous failure on the second subevent fault.

We perform an exhaustive study of coseismic and postseismic surface deformations induced by shear dislocations using flat and spherical Earth models. Our aim is to examine the effects of the spherical geometry, the vertical layering, and the self-gravitation on surface displacement field. For a 100 km long fault, spherical and flat models produce comparable coseismic deformations up to a distance of ∼300 km from the epicenter. This distance is sensibly reduced in the postseismic regime and when infinitely long strike-slip faults are considered. The differences between predictions based on flat and spherical models are due both to their global geometry and the effect of the gravity forces. Self-gravitation has a minor role with respect to that of sphericity for surface coseismic deformations, while in the postseismic regime its effects increase considerably. As a case study, we consider the coseismic and postseismic deformations due to the great 1960 Chilean earthquake. The results of the spherical stratified model differ sensibly from those of a flat uniform model. Moreover, within the framework of spherical Earth models, the rheological stratification plays a major role in determining the pattern of the displacement field. We show that the present-day rates of vertical and horizontal deformations are considerably large (∼10 -2 m yr -1 ) for an asthenospheric viscosity ranging from 10 19 to 10 20 Pa s. These rates, which could possibly be detected by geodetic investigations, are found to be also sensitive to the rheological properties of the mantle beneath the asthenosphere.

Efforts to mathematically model the Earth's post-glacial rebound, or, in general, long-term planetary-scale viscoelastic deformations, have been ongoing for several decades. Unfortunately, research in the post-glacial rebound community has not been characterized by much exchange of knowledge. Groups around the world have developed their code independently, sometimes with profoundly different approaches, occasionally leading to inconsistent results [e.g., Boschi et al., 1999]. Postglacial Rebound Calculator (TABOO) is a post-glacial rebound software that is being made freely available (through Samizdat Press at http://samizdat.mines.edu/taboo/) in the hope that it might become a common reference for all post-glacial rebound researchers. TABOO is portable and has been tested on Unix, Linux, and Windows systems; all it requires is a Fortran90 compiler supporting quadruple precision. The software is easy to use. It comes with a detailed guide that can work as a quick reference cookbook, and it is also accompanied by a textbook, The Theory Behind TABOO, collecting the most significant theoretical results from post-glacial rebound literature. TABOO is not a “black-box,” although it may easily be used as such. The entire source code is provided and should be easy to understand for intermediate-level Fortran programmers.

On August 24, 2016, at 01:36 UTC a ML 6.0 earthquake struck a portion of the Central Apennines between the towns of Norcia and Amatrice. The epicentre was located near the town of Accumoli. Prompt Synthetic Aperture Radar (SAR) acquisitions and the available scientific knowledge of the area allowed to elaborate a first interpretative framework of the ongoing seismic sequence only 30 hours after the mainshock (doi: 10.5281/zenodo.60938) and a second analysis, complete of several Interferometric SAR (InSAR) data within two weeks (doi: 10.5281/zenodo.61682). Through the inversion of InSAR data, we found that the seismogenic structure is oriented NNW-SSE and extends about 20 km between the towns of Norcia and Amatrice with a width of about 10 km. The retrieved slip reaches a maximum value of more than 1.2 m, and stops at a depth of about 4 km. Preliminary fault slip inversions suggest two main patches of co-seismic deformation located NW and SE of the hypocenter. As a final result, we highlight the double fold achievements obtained: a rapid fault identification, and no disadvantage in terms of reliability of the retrieved parameters.

Prefazione a volume divulgativo su Cesare Borgia