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Constraining fault constitutive behavior with slip and stress heterogeneity

Aagaard, B. T. and Heaton, T. H. (2008) Constraining fault constitutive behavior with slip and stress heterogeneity. Journal of Geophysical Research B, 113 (B4). Art. No. B04301 . ISSN 0148-0227. doi:10.1029/2006JB004793. https://resolver.caltech.edu/CaltechAUTHORS:20121128-095555235

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Abstract

We study how enforcing self-consistency in the statistical properties of the preshear and postshear stress on a fault can be used to constrain fault constitutive behavior beyond that required to produce a desired spatial and temporal evolution of slip in a single event. We explore features of rupture dynamics that (1) lead to slip heterogeneity in earthquake ruptures and (2) maintain these conditions following rupture, so that the stress field is compatible with the generation of aftershocks and facilitates heterogeneous slip in subsequent events. Our three-dimensional finite element simulations of magnitude 7 events on a vertical, planar strike-slip fault show that the conditions that lead to slip heterogeneity remain in place after large events when the dynamic stress drop (initial shear stress) and breakdown work (fracture energy) are spatially heterogeneous. In these models the breakdown work is on the order of MJ/m^2, which is comparable to the radiated energy. These conditions producing slip heterogeneity also tend to produce narrower slip pulses independent of a slip rate dependence in the fault constitutive model. An alternative mechanism for generating these confined slip pulses appears to be fault constitutive models that have a stronger rate dependence, which also makes them difficult to implement in numerical models. We hypothesize that self-consistent ruptures could also be produced by very narrow slip pulses propagating in a self-sustaining heterogeneous stress field with breakdown work comparable to fracture energy estimates of kJ/M^2.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/2006JB004793DOIArticle
ORCID:
AuthorORCID
Heaton, T. H.0000-0003-3363-2197
Additional Information:© 2008 American Geophysical Union. Received 10 October 2006; accepted 16 January 2008; published 8 April 2008. We thank Ruth Harris, Paul Spudich, and an anonymous reviewer for comments which led to significant improvements in the manuscript.
Subject Keywords:earthquake; fault constitutive models; slip heterogeneity
Issue or Number:B4
DOI:10.1029/2006JB004793
Record Number:CaltechAUTHORS:20121128-095555235
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20121128-095555235
Official Citation:Aagaard, B. T., and T. H. Heaton (2008), Constraining fault constitutive behavior with slip and stress heterogeneity, J. Geophys. Res., 113, B04301, doi:10.1029/2006JB004793.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:35696
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:28 Nov 2012 21:46
Last Modified:09 Nov 2021 23:17

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