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Frictional Afterslip Following the 2005 Nias-Simeulue Earthquake, Sumatra

Hsu, Ya-Ju and Simons, Mark and Avouac, Jean-Philippe and Galetzka, John and Sieh, Kerry and Chlieh, Mohamed and Natawidjaja, Danny and Prawirodirdjo, Linette and Bock, Yehuda (2006) Frictional Afterslip Following the 2005 Nias-Simeulue Earthquake, Sumatra. Science, 312 (5782). pp. 1921-1926. ISSN 0036-8075. doi:10.1126/science.1126960.

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Continuously recording Global Positioning System stations near the 28 March 2005 rupture of the Sunda megathrust [moment magnitude (M_w) 8.7] show that the earthquake triggered aseismic frictional afterslip on the subduction megathrust, with a major fraction of this slip in the up-dip direction from the main rupture. Eleven months after the main shock, afterslip continues at rates several times the average interseismic rate, resulting in deformation equivalent to at least a M_w 8.2 earthquake. In general, along-strike variations in frictional behavior appear to persist over multiple earthquake cycles. Aftershocks cluster along the boundary between the region of coseismic slip and the up-dip creeping zone. We observe that the cumulative number of aftershocks increases linearly with postseismic displacements; this finding suggests that the temporal evolution of aftershocks is governed by afterslip.

Item Type:Article
Related URLs:
Simons, Mark0000-0003-1412-6395
Avouac, Jean-Philippe0000-0002-3060-8442
Sieh, Kerry0000-0002-7311-2447
Additional Information:© 2006 American Association for the Advancement of Science. Received 2 March 2006; accepted 17 May 2006. Supported by the Gordon and Betty Moore Foundation and the Indonesian International Joint Research Program (RUTI). We thank two anonymous reviewers for constructive comments, as well as R. W. Briggs, H. Perfettini, and A. J. Meltzner for valuable discussions. This is Caltech Tectonics Observatory contribution number 40 and Caltech Seismological Laboratory contribution number 9146.
Group:Caltech Tectonics Observatory, Caltech Tectonics Observatory. Sumatran Plate Boundary, Seismological Laboratory
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
Indonesian International Joint Research Program (RUTI)UNSPECIFIED
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Tectonics Observatory40
Caltech Seismological Laboratory9146
Issue or Number:5782
Record Number:CaltechAUTHORS:20101117-080409426
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:20842
Deposited By: Tony Diaz
Deposited On:17 Nov 2010 19:11
Last Modified:09 Nov 2021 00:03

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