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Off-fault tensile cracks: A link between geological fault observations, lab experiments, and dynamic rupture models

Ngo, D. and Huang, Y. and Rosakis, A. and Griffith, W. A. and Pollard, D. (2012) Off-fault tensile cracks: A link between geological fault observations, lab experiments, and dynamic rupture models. Journal of Geophysical Research B, 117 (B1). Art. No. B01307. ISSN 0148-0227.

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We examine the local nature of the dynamic stress field in the vicinity of the tip of a semi-infinite sub-Rayleigh (slower than the Rayleigh wave speed, c_R) mode II crack with a velocity-weakening cohesive zone. We constrain the model using results from dynamic photoelastic experiments, in which shear ruptures were nucleated spontaneously in Homalite-100 plates along a bonded, precut, and inclined interface subject to a far-field uniaxial prestress. During the experiments, tensile cracks grew periodically along one side of the shear rupture interface at a roughly constant angle relative to the shear rupture interface. The occurrence and inclination of the tensile cracks are explained by our analytical model. With slight modifications, the model can be scaled to natural faults, providing diagnostic criteria for interpreting velocity, directivity, and static prestress state associated with past earthquakes on exhumed faults. Indirectly, this method also allows one to constrain the velocity-weakening nature of natural ruptures, providing an important link between field geology, laboratory experiments, and seismology.

Item Type:Article
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URLURL TypeDescription DOIArticle
Rosakis, A.0000-0003-0559-0794
Additional Information:© 2012 by the American Geophysical Union. Received 10 June 2011; revised 4 November 2011; accepted 16 November 2011; published 20 January 2012. This manuscript benefited from comments and suggestions by the Associate Editor and two anonymous reviewers. Experiments were supported by the U.S. Geological Survey (USGS), Department of Interior, under USGS award 08HQGR0010 to Pollard. Griffith also received support under National Science Foundation (NSF) grant OISE-0754258. Rosakis and Ngo were supported by U.S. Department of Energy grant DE-FG52-06NA 26209, NSF grant EAR-0711545, and Office of Naval Research Multidisciplinary Research Initiative (ONR MURI) grant N0014-06-1-0730.
Funding AgencyGrant Number
U. S. Geological Survey (USGS)08HQGR0010
Department of Energy (DOE)DE-FG52-06NA 26209
Office of Naval Research (ONR)N0014-06-1-0730
Subject Keywords:fault damage; fault mechanics; prestress; shear rupture; sub-Rayleigh; subsonic
Issue or Number:B1
Record Number:CaltechAUTHORS:20120222-085327488
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Official Citation:Ngo, D., Y. Huang, A. Rosakis, W. A. Griffith, and D. Pollard (2012), Off-fault tensile cracks: A link between geological fault observations, lab experiments, and dynamic rupture models, J. Geophys. Res., 117, B01307, doi:10.1029/ 2011JB008577
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:29405
Deposited By: Tony Diaz
Deposited On:29 Feb 2012 00:15
Last Modified:25 Oct 2019 21:49

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