Open AccessOn fault slip zones in the external shear‐field separated by a high rigidity asperity (barrier)—inplane and antiplane strain models
Author(s) -
Rybicki Kacper R.
Publication year - 1989
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1989.tb05253.x
Subject(s) - rigidity (electromagnetism) , shear (geology) , geology , antiplane shear , shear stress , stress field , slip (aerodynamics) , materials science , fissure , geometry , mechanics , geotechnical engineering , seismology , composite material , stress intensity factor , structural engineering , fracture mechanics , finite element method , physics , engineering , mathematics , thermodynamics
SUMMARY Faulting in a medium with an asperity (barrier) is analysed using a model consisting of two colinear shear‐cracks separated by a high rigidity inclusion of circular shape. The dislocation density on the cracks, seismic moment, and the average shear stress induced by the cracks are computed for various rigidity contrasts between the inclusion and the surrounding medium and for different lengths of cracks. The results are similar for cracks of mode II and III when the external shear stress and the frictional stress on the cracks are assumed to be uniform. However, once the external shear stress around the inclusion is taken into consideration, which results in variable stress drop along the cracks, the results for mode II cracks are essentially different from those for mode III cracks. In particular, faulting in mode III is much more sensitive to the rigidity contrast between the inhomogeneity and the surrounding medium than that in mode II, and the seismic moment for cracks in mode III is much higher than that for mode II cracks of same length. This means that the magnitude of elastic parameters of inhomogeneities can significantly effect faulting process, in addition to effects of parameters describing the strength of inhomogeneites.