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Quasi-dynamic versus fully dynamic simulations of earthquakes and aseismic slip with and without enhanced coseismic weakening

Thomas, Marion Y. and Lapusta, Nadia and Noda, Hiroyuki and Avouac, Jean-Philippe (2014) Quasi-dynamic versus fully dynamic simulations of earthquakes and aseismic slip with and without enhanced coseismic weakening. Journal of Geophysical Research. Solid Earth, 119 (3). pp. 1986-2004. ISSN 2169-9313. http://resolver.caltech.edu/CaltechAUTHORS:20140703-104019674

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Abstract

Physics-based numerical simulations of earthquakes and slow slip, coupled with field observations and laboratory experiments, can, in principle, be used to determine fault properties and potential fault behaviors. Because of the computational cost of simulating inertial wave-mediated effects, their representation is often simplified. The quasi-dynamic (QD) approach approximately accounts for inertial effects through a radiation damping term. We compare QD and fully dynamic (FD) simulations by exploring the long-term behavior of rate-and-state fault models with and without additional weakening during seismic slip. The models incorporate a velocity-strengthening (VS) patch in a velocity-weakening (VW) zone, to consider rupture interaction with a slip-inhibiting heterogeneity. Without additional weakening, the QD and FD approaches generate qualitatively similar slip patterns with quantitative differences, such as slower slip velocities and rupture speeds during earthquakes and more propensity for rupture arrest at the VS patch in the QD cases. Simulations with additional coseismic weakening produce qualitatively different patterns of earthquakes, with near-periodic pulse-like events in the FD simulations and much larger crack-like events accompanied by smaller events in the QD simulations. This is because the FD simulations with additional weakening allow earthquake rupture to propagate at a much lower level of prestress than the QD simulations. The resulting much larger ruptures in the QD simulations are more likely to propagate through the VS patch, unlike for the cases with no additional weakening. Overall, the QD approach should be used with caution, as the QD simulation results could drastically differ from the true response of the physical model considered.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1002/2013JB010615DOIArticle
http://onlinelibrary.wiley.com/doi/10.1002/2013JB010615/abstractPublisherArticle
ORCID:
AuthorORCID
Thomas, Marion Y.0000-0002-4335-8841
Lapusta, Nadia0000-0001-6558-0323
Avouac, Jean-Philippe0000-0002-3060-8442
Additional Information:© 2014 American Geophysical Union. Received 28 August 2013; Accepted 22 January 2014; Accepted article online 28 January 2014; Published online 20 March 2014. This study was supported by the National Science Foundation through grant EAR 1142183, the Gordon and Betty Moore Foundation through grant GBMF 423.01 to the Caltech Tectonics Observatory, and the Keck Institute for Spaces Studies at Caltech. This is Tectonics Observatory contribution 255. The numerical simulations for this research were performed on Caltech Division of Geological and Planetary Sciences Dell cluster. We thank reviewers Steve Day and Ruth Harris for insightful detailed comments that helped us improve the manuscript.
Group:Keck Institute for Space Studies, Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFEAR 1142183
Gordon and Betty Moore FoundationGBMF 423.01
Keck Institute for Space Studies (KISS)UNSPECIFIED
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Tectonics Observatory255
Record Number:CaltechAUTHORS:20140703-104019674
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140703-104019674
Official Citation:Thomas, M. Y., N. Lapusta, H. Noda, and J.-P. Avouac (2014), Quasi-dynamic versus fully dynamic simulations of earthquakes and aseismic slip with and without enhanced coseismic weakening, J. Geophys. Res. Solid Earth, 119, 1986–2004, doi:10.1002/2013JB010615.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46810
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:07 Jul 2014 19:37
Last Modified:02 Oct 2017 19:38

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