HR: 1340h
AN: S13D-1087    [Abstracts]
TI: Crustal Tomography Imaging Beneath The Gulf of Corinth Using a new Seismic Dataset Collected in 2002.
AU: * Gautier, S
EM: gautier@geoazur.unice.fr
AF: UMR-Geosciences Azur, CNSR/Universite de Nice Sophia-Antipolis, Sophia Antipolis 250 rue Albert Einstein, Valbonne, 06560 France
AU: Latorre, D
EM: latorre@geoazur.unice.fr
AF: UMR-Geosciences Azur, CNSR/Universite de Nice Sophia-Antipolis, Sophia Antipolis 250 rue Albert Einstein, Valbonne, 06560 France
AU: Deschamps, A
EM: deschamps@geoazur.unice.fr
AF: UMR-Geosciences Azur, CNSR/Universite de Nice Sophia-Antipolis, Sophia Antipolis 250 rue Albert Einstein, Valbonne, 06560 France
AU: Sotiriou, A
EM: sotiriou@upatras.gr
AF: Patras Seismological Laboratory, University of Patras, Rio 261 10, Patras, 26500 Greece
AU: Speretsidaxi, A
EM: speretsidaxi@upatras.gr
AF: Patras Seismological Laboratory, University of Patras, Rio 261 10, Patras, 26500 Greece
AU: Skarpelos, C
EM: skarpelos@upatras.gr
AF: Patras Seismological Laboratory, University of Patras, Rio 261 10, Patras, 26500 Greece
AU: Virieux, J
EM: virieux@geoazur.unice.fr
AF: UMR-Geosciences Azur, CNSR/Universite de Nice Sophia-Antipolis, Sophia Antipolis 250 rue Albert Einstein, Valbonne, 06560 France
AU: Tselentis, A
EM: tselentis@upatras.gr
AF: Patras Seismological Laboratory, University of Patras, Rio 261 10, Patras, 26500 Greece
AB: The Gulf of Corinth is the most active rifting zone of the Mediterranean region. Despite many studies, the crustal structure of this region is still a debating subject, especially for the western part of the Gulf where authors assume the presence of a low-angle detachment lying at 9-11 km depth. In this study, we construct improved mid-crust velocity models and accurate earthquake locations in order to provide new constraints on the tectonic and the geodynamic framework of the Corinth region, thanks to the new large dataset collected during the 3F-Corinth project around the Aigion area in 2002. The tomographic method we use is based on both an accurate finite-difference travel-time computation and a linearized iterative inversion scheme. P- and S- first-arrival times are simultaneously inverted for both earthquake locations and velocity distribution. Relocation of sources is also obtained from double difference procedures in order to highlight the active structures. A cross-correlation method is applied to the selected dataset for the improvement of the quality of the time picking catalog. The retrieved Vp and Vs models and the absolute location of events allow to image the mid-crust structure. The deduced Vp/Vs and Vp*Vs images give us additional information about the spatial distribution of porosity and fluid content. These results indicate the presence of two different zones with depth. The first 5 km corresponds to the shallower zone which is controlled by the NS extension and where we observe a lack of seismicity. The deeper zone (7-13 km) is characterized by faster and more heterogeneous anomalies. Moreover this zone matches the seismogenic zone. Our images confirm previous tomographic results obtained from data collected in 1991 in the same area with a less dense network and their interpretation can provide new insights on the presence and the nature of an active low-angle detachment in the western Gulf.
DE: 7260 Theory and modeling
DE: 7299 General or miscellaneous
DE: 7209 Earthquake dynamics and mechanics
DE: 7218 Lithosphere and upper mantle
SC: Seismology [S]
MN: 2004 AGU Fall Meeting