HR: 1340h
AN: S43A-1048    [Abstracts]
TI: Relationship Between Characteristics of Dynamic Stress Changes and Rupture Process on a Dipping Fault
AU: * Kimura, T
EM: tkimura@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, University of Tokyo, 1-1-1, Yayoi, Bunkyo, Tokyo, 113-0032 Japan
AU: Miyatake, T
EM: miyatake@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, University of Tokyo, 1-1-1, Yayoi, Bunkyo, Tokyo, 113-0032 Japan
AB: We investigate a relationship between spatio-temporal variations of dynamic changes of Coulomb failure function (ΔCFF) and rupture process on a dipping fault. In order to understand earthquake triggering, many researchers have compared ΔCFF due to preceding earthquakes with following seismicity rate changes, and indicated good correlations for many earthquakes. Sometimes, they have used a realistic heterogeneous rupture model and obtained a complex ΔCFF distribution which is caused by a faulting process. However, the relationship between spatial and temporal variations of dynamic ΔCFF and source process on the master fault is not clearly understood except for a strike slip earthquake propagating along a fault strike. In this study, by using a simple fault model on which slip is perpendicular to the rupture propagation, corresponding to a dipping fault propagating along a fault strike such as the 2004 Mid Niigata Prefecture, Japan, earthquake, we indicate relations between characteristics of the dynamic stress changes and the rupture process. We calculate dynamic stress changes in an infinite homogeneous elastic medium by using the forth-order finite difference method (FDM) with 3D staggered-grid. As characteristics of the calculated dynamic ΔCFF, we give following three points. Firstly, according to the sign of the normal stress, four separate parts appears in the spatial distribution of ΔCFF. This characteristic is seen in both the static and the dynamic ΔCFF distribution, and following two characteristics are seen only in the dynamic ΔCFF distribution. Secondly, dynamic ΔCFF is amplified as the rupture propagates because of rupture directivity effect which is not stronger than a strike slip fault. Finally, stopping phase with large amplitude is radiated when the rupture reaches to the edge of the fault, and it causes lobes with large ΔCFF values extending in the direction perpendicular to the master fault from the fault edge.
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
DE: 7290 Computational seismology
SC: Seismology [S]
MN: Fall Meeting 2005