A5027761636- earthquake and tectonic studies
- Seismology and Earthquake Studies
- Seismic Waves and Analysis
- High-pressure geophysics and materials
- Earthquake Detection and Analysis
- Seismic Imaging and Inversion Techniques
- Geological and Geophysical Studies Worldwide
- Geological and Geochemical Analysis
- Geophysical and Geoelectrical Methods
- Geological formations and processes
- Geological and Geophysical Studies
- Geophysical Methods and Applications
- Archaeological and Historical Studies
- Geology and Paleoclimatology Research
- Geochemistry and Geologic Mapping
- Probabilistic and Robust Engineering Design
- Methane Hydrates and Related Phenomena
- Adhesion, Friction, and Surface Interactions
- Geological Studies and Exploration
- Karst Systems and Hydrogeology
- Granular flow and fluidized beds
- Geotechnical and Geomechanical Engineering
- Island Studies and Pacific Affairs
- CO2 Sequestration and Geologic Interactions
- Geophysics and Sensor Technology
Observatoire Midi-Pyrénées
2020-2024
Institut de Recherche en Astrophysique et Planétologie
2019-2024
Université Toulouse III - Paul Sabatier
2019-2024
Centre National de la Recherche Scientifique
2012-2024
Université de Toulouse
2023
Université Grenoble Alpes
2017-2019
Institut des Sciences de la Terre
2013-2019
Université Savoie Mont Blanc
2017-2019
Université Gustave Eiffel
2014-2019
Institut de Recherche pour le Développement
2018-2019
To gain a better insight of the hydrogeology and location main tectonic faults Stromboli volcano in Italy, we collected electrical resistivity measurements, soil CO2 concentrations, temperature self-potential measurements along two profiles. These profiles started at village Ginostra southwest part island. The first profile (4.8 km length) ended up Scari north east second one (3.5 Forgia Vecchia beach, eastern data were used to provide insights regarding position shallow aquifers extension...
A series of pyroclastic density currents were generated at Tungurahua volcano (Ecuador) during a period heightened activity in August 2006. Dense flows confined to valleys the drainage network, while dilute overflowed on interfluves where they deposited isolated bodies comprising dune bedforms cross-stratified ash exposed surface. Here, description, measurement, and classification more than 300 are presented. Four types identified with respect their shape, internal structure, geometry...
The deposits of the pyroclastic density currents from August 2006 eruption Tungurahua show three facies associations depending on topographic setting: massive, proximal cross-stratified, and distal cross-stratified facies. (1) massive is confined to valleys slopes volcano. It contains clasts >1 m diameter fine ash material, interpreted as deposited dense flows. Its surface can exhibit lobes levees covered with disk-shaped vesicular large clasts. These fragile must have rafted at flows all...
Abstract In this study we explore experimentally the effects of fault heterogeneity on rupture nucleation. We conducted friction experiments between two polycarbonate plates, with a periodically heterogeneous interface. The propagation is monitored an ultra‐fast video camera by taking advantage photo‐elastic properties material used. show that nucleation process does not always consists monotonic growth velocity. Instead, front advances alternation slow and fast episodes accelerates until it...
We present the first 3 months of aftershock activity following 2015 April 25 Gorkha earthquake Mw 7.8 recorded on Nepalese Seismic network. deployed an automatic procedure composed three main stages: (1) coarse determination P and S onsets; (2) phase association to declare events (3) iterative addition refinement onsets using Kurtosis characteristic function. In total 9188 could be located in Kathmandu region with majority having small location errors (<4.5, 9 10 km X-, Y- Z-directions,...
Abstract Fumaroles are a common manifestation of volcanic activity that associated with large emissions gases into the atmosphere. These originate from magma, and they can provide indirect unique insights magmatic processes. Therefore, extensively used to monitor forecast eruptive activity. During their ascent, interact rock hydrothermal fluids, which modify geochemical compositions. interactions complicate our understanding real dynamics remain poorly considered. Here, we present first...
SUMMARY The Lacq area in southwest France has been associated with continuous moderate induced seismic activity since 1969. However, the mechanisms driving this seismicity are not fully understood: reservoir depletion proposed as main factor, and more recently wastewater injection suggested to play a important role. interpretation of these relies heavily on quality earthquake locations, which we prove be weak due lack local instrumentation for several years. In order provide most complete...
Located in the heart of Bolivian orocline, Cochabamba department and its two million inhabitants are exposed to frequent seismic activity. However, tectonic structures causing these earthquakes remain poorly identified. Indeed, Bolivia’s national seismological network does not optimally cover area hypocentral locations local therefore subject large uncertainties which hinder their association with specific faults. We established a regional consisting 11 broadband short-period stations,...
Mongolian tectonics is shaped by the far-reaching effects of Indo-Eurasian collision, which drives deformation and stress over 2000 km behind Himalayan front. During 20th century, Mongolia experienced four earthquakes with magnitudes greater than 8, making it an exceptional location for studying intraplate seismicity, predominantly strike-slip components. Among these events, Tsetserleg-Bulnay fault system recorded largest earthquake doublet, two magnitude 8 occurring 14 days apart in 1905,...
We used strong-motion records from the 2012 May 20 and 29 Emilia-Romagna earthquakes (Mw 6.1 5.9, respectively) four aftershocks with magnitudes ranging between 4.9 5.5 to analyse S-wave spectral amplitude decay distance estimate acceleration source functions site effects. The data set consists of six earthquakes, 44 stations 248 hypocentral distances in range 10 < r 100 km. rotated accelerograms calculate transverse radial components spectrum. found non-parametric attenuation that describe...
The depth of 61 aftershocks the 2015 April 25 Gorkha, Nepal earthquake, that occurred within first 20 d following main shock, is constrained using time delays between teleseismic P phases and (pP sP). detection identification these are automatically processed cepstral method developed by Letort et al., validated with computed radiation patterns from most probable focal mechanisms. events found to be relatively shallow (13.1 ± 3.9 km). Because estimations could potentially biased method,...
SUMMARY Unravelling relations between lateral variations of mid-crustal seismicity and the geometry Main Himalayan Thrust (MHT) system at depth is a key issue in seismotectonic studies range. These can reveal along strike changes behaviour fault related to fluids or local ramp-flat more generally stress build-up fault. Some these may control rupture extension intermediate, large great earthquakes, last which dates back from 1505 CE far western Nepal. The region also associated...
Abstract Since the M w 7.9 Gorkha earthquake of April 25, 2015, seismicity central and western Nepalese Himalaya has been monitored by an increasing number permanent seismic stations. These instruments contribute to location thousands aftershocks that occur at margin segment Main Himalayan Thrust (MHT) ruptured in 2015. They also help constrain clusters originated periphery fault earthquake, which may indicate a migration along system. We report here crisis followed Lamjung moderate 4.7...
The Solfatara is one of the major volcanoes Phlegrean Fields (Campi Flegrei) volcanic complex, and it located in a densely populated area few kilometres west city Naples. It an active resurgent caldera that has been characterized by rich history surface–ground deformation soil diffuse degassing fumarolic emissions, which are indications top hydrothermal plume. A seismic survey was completed May 2009 for characterization main subsurface features Solfatara. Using complete data set, we have...
Seismic monitoring of southwestern France began in the 1960s, and homogeneous coverage by observation networks has been place since 1990s. The accumulation data now allows a refined understanding regional seismicity, not only on its spatial aspects, but also regularity earthquake distribution over time. This paper is both review work carried out subject, progress report current knowledge seismicity seismotectonic context. With support maps, available catalogs are exploited at different...
Research Article| February 04, 2014 Moderate Earthquake Teleseismic Depth Estimations: New Methods and Use of the Comprehensive Nuclear‐Test‐Ban Treaty Organization Network Data J. Letort; Letort aCEA/DAM/DIF, F‐91297 Arpajon, Francejean.letort@ujf-grenoble.frjulien.vergoz@cea.frjocelyn.guilbert@cea.frOlivier.sebe@cea.fryoann.cano@cea.fr Search for other works by this author on: GSW Google Scholar Vergoz; Vergoz Guilbert; Guilbert F. Cotton; Cotton bInstitut des Sciences de la Terre...
The depth of an earthquake is difficult to estimate because the trade-off between and origin time estimations, it can be biased by lateral Earth heterogeneities. To face this challenge, we have developed a new, blind fully automatic teleseismic analysis. results new method do not depend on epistemic uncertainties due depth-phase picking identification. consists modification cepstral analysis from Letort et al. Bonner al., which aims detect surface reflected (pP, sP) waves in signal at...
Abstract The observation of a transient slip 1 month before the rupture 2011 Tohoku earthquake is conandrum since area was supposedly fully coupled. A better understanding mechanisms at work during preseismic phase thus fundamental. However, configuration Pacific plate and location zone 200 km from coast make it difficult to detect microseismic events. In this study, we use multidimensional template matching (MDTM) technique earthquakes that are hidden in noise. temporal distribution these...
SUMMARY An unusual seismic activity has recently occurred in the Gripp valley, located central part of French Pyrenees. Since spring 2020, two new swarms appeared, clearly outside usual location seismicity this area. On 20 September almost concomitantly with activation second swarm, a hole suddenly opened bed local river, Adour de Payolle. This drained water from which dried up over 500 m. We follow and study spatial temporal evolution these clusters, using four temporary stations deployed...
SUMMARY Earthquake hypocentres are routinely obtained by a common inversion problem of P- and S-phase arrivals observed on seismological network. Improving our understanding the uncertainties associated with hypocentral parameters is crucial for reliable analysis, tectonic processes seismic hazard assessment. However, current methods often overlook in velocity models variable trade-offs during inversion. Here, we propose to unravel effects main sources uncertainty location process using...
Detections of pP and sP phase arrivals (the so-called depth phases) at teleseismic distance provide one the best ways to estimate earthquake focal depth, as P–pP P–sP delays are strongly dependent on depth. Based a new processing workflow using single seismic array distance, we can clusters small events down magnitude Mb 3.5. Our method provides direct view relative variations seismicity from an active area. This study focuses application this methodology lateral Guerrero subduction zone...