DESCHAMPS , Anne

An investigation of the teleseismic P-wave coda is performed using the single-scattering approximation. The method allows one to image short-wavelength scale (≤2 km) velocity and density heterogeneities and structures that are barely detected by traveltime tomography. Source effects are removed by using receiver functions for data...

The presence of two regional seismic networks in southeastern France provides us high-quality data to investigate upper mantle flow by measuring the splitting of teleseismic shear waves induced by seismic anisotropy. The 10 three-component and broadband stations installed in Corsica, Provence, and western Alps efficiently complete the...

We propose an inversion method of the direct wave amplitudes P, SV, and SH to determine the general moment tensor (MT) and estimate the associated uncertainties. This method is a generalization of the one we developed to determine the double-couple (DC) or fault-plane solution from sparse observations in reservoir contexts (Godano et al.,...

The mean magnitude of earthquakes in the Gulf of Corinth is found to increase strongly with depth (b-value decreases), whereas the dip of fault planes decreases. The b-value difference of 0.25, between shallow and deep earthquake distributions, is based on about 7,000 events and therefore is statistically highly significant. The same is true in...

International audience

Teleseismic travel times recorded along a 1000 km-long, ∼N-S transect across central Mongolia are used together with topography and gravity data to constrain the deep lithospheric structure of this region. Time residuals appear positively correlated with the topography, suggesting that P-wave velocity changes correspond to density variations...

Soil Dynamics and Earthquake Engineering, vol. 17, pp. 475-484, 1998

The soil-structure interaction (SSI) is generally neglected for seismic design of ordinary buildings. A modeling technique is proposed to facilitate the integration of SSI in building design, considering rocking effects and the shallow foundation deformability. The proposed technique is suitable when the soil can be considered as horizontally...

The primary processes driving seismic swarms are still under debate. Here, we study the temporal evolution of a seismic swarm that occurred over a 10-day period in October 2015 in the extensional rift of the Corinth Gulf (Greece) using high-resolution earthquakes relocations. The seismicity radially migrates on a normal fault at a fluid...

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We present a two-stage method to simulate the ground motions produced by an earthquake by using stochastic summation of small earthquakes. In this method, identical small earthquakes are multiplied by a scaling factor and summed together with time delays randomly distributed, during the two stages, over the source duration. The summation scheme...

A propos des vibrations du sol dues à un séisme Un séisme est dû à une rupture des roches en profondeur qui occasionne un déplacement rapide des deux compartiments d'une faille. C'est un phénomène bref (quelques secondes pour les séismes faibles à modérés à quelques minutes pour les séismes majeurs) qui génère des vibrations appelées ondes...

Plusieurs failles actives sont identifiées à la jonction Alpes – Bassin Ligure : des failles dont la longueur est de l'ordre de la dizaine de kilomètres à terre (Faille de Blausasc, Faille de Donareo, Faille de Saorge-Taggia) et en mer le système de faille nord Ligure dont la longueur totale atteint 80 km. La géométrie et la cinématique de ces...

The 26 December 2004 Indian Ocean tsunami damaged severely most of the Gulf of Bengal's coastal areas, but the coast of Bangladesh which stands at the edge of an extraordinarily extended continental shelf. This latter feature has been built through huge discharges of river sediments along the Brahmaputra and Ganges rivers. As a result of this...

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The purpose of this article is to address the problem of the focal mechanism determination using few seismological records acquired by a sparse network of 3-component sensors. Such cases are frequently encountered in reservoir contexts for the monitoring of the fluid-induced microseismicity. Focal mechanisms of fluid-induced earthquakes are...

In this study, we explore the origin of lower crustal seismicity and the factors controlling rift propagation using seismological data recorded within the youngest part of the East African Rift System, the North Tanzanian Divergence (NTD). Most earthquakes below Lake Manyara occur at depth ranging between 20 and 40 km and have a swarm-like...

This study investigates a microseismic swarm induced by injection operations in the Arkema-Vauvert salt field. The seismic activity in this field is monitored only by two permanent 3-component stations deployed in two wells. This study focuses on a period of 21 months (2004 January-2005 September) during which 1214 seismic events are located....

The local measurement of dispersion curves of intermediate-period surface waves is particularly difficult because of the long wavelengths involved. We suggest an improved procedure for measuring dispersion curves using small-aperture broad-band arrays. The method is based on the hypotheses of plane incoming waves and that averaging over a set...

Understanding how fluids pressure produce seismic or aseismic motion along faults is an important goal for seismic hazard assessment and for geological reservoir monitoring. Seismicity rate increase in fluid injection areas where some events may reach magnitude greater than 5. Besides, the microseismicity is one the few tools used to follow...

International audience

Le rift de Corinthe, en Grèce, séparant le Péloponnèse (au sud) du continent (au nord), est l'une des structures tectoniques en extension les plus actives dans le monde. Il est asymétrique avec des failles actives marquées affleurant au sud, les plus jeunes étant sous l'eau. Ces failles se connectent en profondeur sur une zone sismique...