HR: 0800h
AN: S21B-0558 [Abstracts]
TI: Dynamic ruptures along bimaterial interfaces in 3D
AU: * Brietzke, G
EM: brietzke@geophysik.uni-muenchen.de
AF: Department of Earth and Environmental Sciences
LMU Munich, Theresienstrasse 41, Munich, 80333, Germany
AU: Cochard, A
EM: alain@geophysik.uni-muenchen.de
AF: Ecole et Observatoire des Sciences de la Terre, Strasbourg, 5, rue Rene Decartes,
Strasbourg, 67084, France
AU: Igel, H
EM: igel@geophysik.uni-muenchen.de
AF: Department of Earth and Environmental Sciences
LMU Munich, Theresienstrasse 41, Munich, 80333, Germany
AB:
Large faults with a long slip history often separate rocks of different elastic properties. Such bimaterial interfaces
have been reported to accommodate remarkable dynamic properties in the 2D in-plane case that may be relevant
to many issues of earthquake rupture dynamics. Slip along a bimaterial interface generates dynamic changes of
normal stress, modifying the local fault strength which, in principle, can generate a unilateral wrinkle-like pulse.
This mechanism is neither present in the homogeneous case nor the 2D anti-plane case. Recently it has been
shown that some of these properties stay valid also in the 3D case where there is a mixing of the in-plane and
anti-plane case.
However, the relevance of this mechanism for natural faulting is a subject of ongoing debate. Independently there
are good examples for which the bimaterial mechanism seems to be necessary to properly interpret the
observations: Asymmetric alongstrike distribution of aftershocks and asymmetric rock damage across faults of
the San Andreas system have been reported.
The uncertainty in the basic physical concepts and the constraints of their parameter ranges makes it difficult to
come to definite conclusions. Here we present results of an ongoing numerical investigation of bimaterial
ruptures in 3D extending the parameter range and resolution of previous studies.
DE: 0545 Modeling (4255)
DE: 7200 SEISMOLOGY
DE: 7209 Earthquake dynamics (1242)
DE: 7290 Computational seismology
SC: Seismology [S]
MN: 2007 Fall Meeting