Granular packings and fault zones
The failure of a two-dimensional packing of elastic grains is analyzed using a numerical model. The packing fails through formation of shear bands or faults. During failure there is a separation of the system into two grain-packing states. In a shear band, local "rotating bearings" are spontaneously formed. The bearing state is favored in a shear band because it has a low stiffness against shearing. The "seismic activity" distribution in the packing has the same characteristics as that of the earthquake distribution in tectonic faults. The directions of the principal stresses in a bearing are reminiscent of those found at the San Andreas Fault.
Astrom
JA
Department of Physics, University of Jyvaskyla, P.O. Box 35, FIN-40351 Jyvaskyla, Finland.
Herrmann
HJ
Timonen
J