HR: 0830h
AN: S41C-0104    [PDF]
TI: Scenario Earthquake in the Moyenne Durance, Southeastern France
AU: Berge-Thierry, C
EM: catherine.berge@irsn.fr
AF: Institut de Radioprotection et de S\^uret\'e Nucl\'eaire, Bureau d'Evaluation des Risques Sismiques pour la S\^uret\'e des Installations Nucl\'eaires, BP17, Fontenay-aux-Roses, 92262 France
AU: * Aochi, H
EM: hideo.aochi@irsn.fr
AF: Institut de Radioprotection et de S\^uret\'e Nucl\'eaire, Bureau d'Evaluation des Risques Sismiques pour la S\^uret\'e des Installations Nucl\'eaires, BP17, Fontenay-aux-Roses, 92262 France
AU: Cushing, E
EM: edward.cushing@irsn.fr
AF: Institut de Radioprotection et de S\^uret\'e Nucl\'eaire, Bureau d'Evaluation des Risques Sismiques pour la S\^uret\'e des Installations Nucl\'eaires, BP17, Fontenay-aux-Roses, 92262 France
AU: Scotti, O
EM: oona.scotti@irsn.fr
AF: Institut de Radioprotection et de S\^uret\'e Nucl\'eaire, Bureau d'Evaluation des Risques Sismiques pour la S\^uret\'e des Installations Nucl\'eaires, BP17, Fontenay-aux-Roses, 92262 France
AU: Volant, P
EM: philippe.volant@irsn.fr
AF: Institut de Radioprotection et de S\^uret\'e Nucl\'eaire, Bureau d'Evaluation des Risques Sismiques pour la S\^uret\'e des Installations Nucl\'eaires, BP17, Fontenay-aux-Roses, 92262 France
AB: The fault system of the Moyenne Durance, southeastern France, is a segmented fault system characterized by a moderate instrumental seismicity. Nevertheless, repeated historical events (M=5-5.5 every century since 1509) and paleoseismological evidence of a possible strong earthquake between 27 ky and 9 ky underline the importance of seismic hazard in this region. Recent studies have revealed a fault system characterized by a complex geometry of fault segments. A critical question for hazard assessment is which segments (or how many segments) are able to break at the same time during an earthquake. This may give a physical constraint on seismic hazard assessment and strong ground motion prediction in this region. The complexity here is the existence of different fault kinematics, a mixture of inverse and left-lateral strike-slip faulting as well as a 3D fault geometry. For this purpose, we simulate spontaneous rupture process along a geometrically complex fault system using a 3D boundary integral equation method (BIEM). Two fault segments are considered: a roughly E-W north dipping structure that meets a NE-SW almost vertical fault. As a preliminary case, we suppose uniform frictional parameters for all segments in the fault system, a uniform tectonic stress with the maximum principal stress $\sigma_1$ NNW oriented and the minimum principal stress $\sigma_3$ vertical, and a fixed fault geometry. The parameters controlling these simulations are the coefficient of friction (static and dynamic), the direction and magnitude of the principal stresses and the distance between the fault segments. Assuming that the value of the dynamic friction is 20-30% less than the static one (0.6), rupture propagation from one segment to the next is only observed when the magnitude of $\sigma_2$ is sufficiently close to $\sigma_3$ and when fault separation is less than 2 km. Future work will consider scenarios along other fault segments as well as considering the possibility that the stress regime may change spatially along the fault system.
DE: 7209 Earthquake dynamics and mechanics
DE: 7215 Earthquake parameters
DE: 7223 Seismic hazard assessment and prediction
DE: 7230 Seismicity and seismotectonics
SC: Seismology [S]
MN: 2003 Fall Meeting