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Spectral-element simulations of long-term fault slip: Effect of low-rigidity layers on earthquake-cycle dynamics

Kaneko, Y. and Ampuero, J.-P. and Lapusta, N. (2011) Spectral-element simulations of long-term fault slip: Effect of low-rigidity layers on earthquake-cycle dynamics. Journal of Geophysical Research B, 116 (B10). Art. No. B10313. ISSN 0148-0227. http://resolver.caltech.edu/CaltechAUTHORS:20111121-115155076

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Abstract

We develop a spectral element method for the simulation of long-term histories of spontaneous seismic and aseismic slip on faults subjected to tectonic loading. Our approach reproduces all stages of earthquake cycles: nucleation and propagation of earthquake rupture, postseismic slip and interseismic creep. We apply the developed methodology to study the effects of low-rigidity layers on the dynamics of the earthquake cycle in 2-D. We consider two cases: small (M ~ 1) earthquakes on a fault surrounded by a damaged fault zone and large (M ~ 7) earthquakes on a vertical strike-slip fault that cuts through shallow low-rigidity layers. Our results indicate how the source properties of repeating earthquakes are affected by the presence of a damaged fault zone with low rigidity. Compared to faults in homogeneous media, we find (1) reduction in the earthquake nucleation size, (2) amplification of slip rates during dynamic rupture propagation, (3) larger recurrence interval, and (4) smaller amount of aseismic slip. Based on linear stability analysis, we derive a theoretical estimate of the nucleation size as a function of the width and rigidity reduction of the fault zone layer, which is in good agreement with simulated nucleation sizes. We further examine the effects of vertically-stratified layers (e.g., sedimentary basins) on the nature of shallow coseismic slip deficit. Our results suggest that low-rigidity shallow layers alone do not lead to coseismic slip deficit. While the low-rigidity layers result in lower interseismic stress accumulation, they also cause dynamic amplification of slip rates, with the net effect on slip being nearly zero.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/2011JB008395DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/2011JB008395/abstractPublisherArticle
ORCID:
AuthorORCID
Ampuero, J.-P.0000-0002-4827-7987
Lapusta, N.0000-0001-6558-0323
Additional Information:© 2011 American Geophysical Union. Received 26 March 2011; revised 1 July 2011; accepted 15 July 2011; published 29 October 2011. This study was supported by the National Science Foundation (grants EAR‐0548277 and EAR‐0944288), the Southern California Earthquake Center (SCEC), and the Gordon and Betty Moore Foundation. SCEC is funded by NSF cooperative agreement EAR‐0106924 and USGS cooperative agreement 02HQAG0008. The SCEC contribution number for this paper is 1477. This is Caltech Tectonics Observatory contribution 161. We thank Eun‐Seo Choi, Billy Landuyt, Ittai Kurzon, and Chris Davies for general discussion on numerical methods. The reviews by Brad Aagaard and an anonymous reviewer helped us improve the manuscript.
Group:Caltech Tectonics Observatory, Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFEAR‐0548277
NSFEAR‐0944288
Southern California Earthquake Center (SCEC)UNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
NSFEAR‐0106924
USGS02HQAG0008
Subject Keywords:earthquake cycle dynamics; earthquake source physics; fault damage zones; numerical simulations; rate and state friction
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Southern California Earthquake Center (SCEC)1477
Caltech Tectonics Observatory161
Record Number:CaltechAUTHORS:20111121-115155076
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20111121-115155076
Official Citation:Kaneko, Y., J.‐P. Ampuero, and N. Lapusta (2011), Spectral‐element simulations of long‐term fault slip: Effect of low‐rigidity layers on earthquake‐cycle dynamics, J. Geophys. Res., 116, B10313, doi:10.1029/2011JB008395.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:27895
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:22 Nov 2011 15:50
Last Modified:01 Sep 2017 19:00

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