Journal Article

Apparent critical slip displacement caused by the existence of a fault zone

Teruo Yamashita and Eiichi Fukuyama

in Geophysical Journal International

Volume 125, issue 2, pages 459-472
Published in print May 1996 | ISSN: 0956-540X
Published online May 1996 | e-ISSN: 1365-246X | DOI: http://dx.doi.org/10.1111/j.1365-246X.1996.tb00011.x
Apparent critical slip displacement caused by the existence of a fault zone

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Summary

We study the influence of a fault zone on the critical slip displacement that is estimated seismologically outside the fault zone theoretically. It is generally known that the critical slip displacement plays a key role in characterizing the earthquake rupture process. the fault zone is modelled as a zone in which a number of parallel pre-existing cracks are distributed. A relatively simple rupture model is assumed in the analysis to elicit only the fundamental effect of dynamic interactions among the cracks on the estimate of the critical slip displacement. the rupture is assumed to occur instantaneously over each crack, and crack lengths are fixed in the analysis. the multiple interactions among the cracks are treated rigorously in the time domain using the boundary-integral equation method.

Our calculation shows that apparent slip-weakening behaviour is observed outside the fault zone, and that it is caused by elastic-wave scattering due to the cracks distributed in the fault zone. the apparent critical slip displacement is shown to be larger when the distribution density of the pre-existing cracks is larger and/or the fault zone width is greater. It is also shown that the apparent critical slip displacement caused by crack scattering is generally larger than the critical slip displacement inherent in the rupture. As the distribution density of the pre-existing cracks increases, the difference in both displacements tends to increase.

Keywords: cracks; earthquakes; fault slip

Journal Article.  0 words. 

Subjects: Geophysics

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