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Off-fault secondary failure induced by a dynamic slip pulse

James R. Rice, Charles G. Sammis and Robert Parsons
Off-fault secondary failure induced by a dynamic slip pulse
Bulletin of the Seismological Society of America (February 2005) 95 (1): 109-134

Abstract

We develop a 2D slip-weakening description of a self-healing slip pulse that propagates dynamically in a steady-state configuration. The model is used to estimate patterns of off-fault secondary failure induced by the rupture, and also to infer fracture energies G for large earthquakes. This extends an analysis for a semi-infinite rupture (Poliakov et al., 2002) to the case of a finite slipping zone length L of the pulse. The dynamic stress drop, when divided by the drop from peak to residual strength, determines the ratio of L to the slip-weakening zone length R. Predicted off-fault damage is controlled by that scaled stress drop, static and dynamic friction coefficients, rupture velocity, principal prestress orientation, and poroelastic Skempton coefficient. All damage zone lengths can be scaled by R (super *) (sub 0) , which is proportional G/(strength drop) (super 2) and is the value of R in the low-rupture-velocity, low-stress-drop, limit. In contrast to the Poliakov et al. (2002) case R/L = 0, the region that supports Coulomb failure reaches a maximum size on the order of R (super *) (sub 0) when mode II rupture speed approaches the Rayleigh speed. Analysis of slip pulses documented by Heaton (1990) leads to estimates of G, each with a factor-of-two model uncertainty, from 0.1 to 9 MJ/m (super 2) (including the factor), averaging 2-4 MJ/m (super 2) ; G tends to increase with the amount of slip in the event. In most cases, secondary faulting should extend, at high rupture speeds, to distances from the principal fault surface on the order of 1 to 2 R (super *) (sub 0) nearly equal 1-80 m for a 100-MPa strength drop; that distance should vary with depth, being larger near the surface. We also discuss gouge and damage processes.


ISSN: 0037-1106
EISSN: 1943-3573
Coden: BSSAAP
Serial Title: Bulletin of the Seismological Society of America
Serial Volume: 95
Serial Issue: 1
Title: Off-fault secondary failure induced by a dynamic slip pulse
Affiliation: Harvard University, Department of Earth and Planetary Sciences and Division of Engineering and Applied Sciences, Cambridge, MA, United States
Pages: 109-134
Published: 200502
Text Language: English
Publisher: Seismological Society of America, Berkeley, CA, United States
References: 93
Accession Number: 2005-038779
Categories: Seismology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
Secondary Affiliation: University of Southern California, USA, United StatesHarvard University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 200523
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