Multi-Physics Couplings and Strain Localization in Seismic Faults
Jean Sulem
Ecole des ponts Paris Tech
ABSTRACT: Sulem’s research interests are related to constitutive modeling of geomaterials, experimental rock mechanics, thermo-hydro-mechanical behavior of geomaterials with applications to tunneling, petroleum engineering, deep geological storage, and fault mechanics. Sulem presents some recent results on analytical and numerical modeling of strain localization processes under multi-physical couplings. Thermo-chemo-mechanical couplings are more and more identified as factors that play a central role in the mechanical behavior and the evolution of localized deformation zones. Field observations of mature faults, i.e. those that have experienced large slip, show evidence that shear deformation is localized in a very narrow zone, a few millimeters in thickness. The width of the deforming zone is a key parameter, as narrow deforming zones concentrate the frictional heating, which leads to large temperature rises and thus to more rapid weakening. Important challenges and questions span from the qualitative understanding of the main phenomena to their quantitative description and observation. Sulem discusses the geophysical implications of these instabilities for earthquake nucleation.
