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Postseismic relocking of the subduction megathrust following the 2007 Pisco, Peru, earthquake

Remy, D. and Perfettini, H. and Cotte, N. and Avouac, J. P. and Chlieh, M. and Bondoux, F. and Sladen, A. and Tavera, H. and Socquet, A. (2016) Postseismic relocking of the subduction megathrust following the 2007 Pisco, Peru, earthquake. Journal of Geophysical Research. Solid Earth, 121 (5). pp. 3978-3995. ISSN 2169-9313. http://resolver.caltech.edu/CaltechAUTHORS:20160909-095219599

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Abstract

Characterizing the time evolution of slip over different phases of the seismic cycle is crucial to a better understanding of the factors controlling the occurrence of large earthquakes. In this study, we take advantage of interferometric synthetic aperture radar data and 3.5 years of continuous Global Positioning System (GPS) measurements to determine interseismic, coseismic, and postseismic slip distributions in the region of the 2007, M_w 8.0 Pisco, earthquake, Peru, using the same fault geometry and inversion method. Our interseismic model, based on pre-2007 campaign GPS data, suggests that the 2007 Pisco seismic slip occurred in a region strongly coupled before the earthquake while afterslip occurred in low coupled regions. Large afterslip occurred in the peripheral area of coseismic rupture in agreement with the notion that afterslip is mainly induced by coseismic stress changes. The temporal evolution of the region of maximum afterslip, characterized by a relaxation time of about 2.3 years, is located in the region where the Nazca ridge is subducting, consistent with rate-strengthening friction promoting aseismic slip. We estimate a return period for the Pisco earthquake of about 230 years with an estimated aseismic slip that might account for about 50% of the slip budget in this region over the 0–50 km seismogenic depth range. A major result of this study is that the main asperity that ruptured during the 2007 Pisco earthquake relocked soon after this event.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1002/2015JB012417DOIArticle
http://onlinelibrary.wiley.com/doi/10.1002/2015JB012417/abstractPublisherArticle
ORCID:
AuthorORCID
Avouac, J. P.0000-0002-3060-8442
Additional Information:© 2016 American Geophysical Union. Received 22 JUL 2015; Accepted 28 APR 2016; Accepted article online 3 MAY 2016; Published online 27 MAY 2016. ASAR data were provided by the European Space Agency (ESA) through the project Envisat-AO857 and category 1 2899. PALSAR data from the ALOS satellite mission operated by the Japanese Aerospace Exploration Agency (JAXA) were used under the terms and conditions of the fourth ALOS 2 Research Announcement (project 1142). This work was supported by the Institut de Recherche pour le Développement (IRD). We thank the people from Laguna Grande village for their great support. We thank Nino Puma Sacsi for this precious help in maintaining station LAGU operational and Alberto Zheimer for supporting the network from day 70 to day 220. Some of the figures were prepared using the GMT software [Wessel and Smith, 1991]. The data for this paper are available by contacting the corresponding author at remy@ird.fr. We thank Lisa Christiansen for editing the text. The Assistant Editor and an anonymous reviewer provided useful and constructive remarks that greatly improved this study.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
Institut de Recherche pour le Développement (IRD)UNSPECIFIED
Subject Keywords:GPS; InSAR; seismic cycle; postseismic slip; slip budget
Record Number:CaltechAUTHORS:20160909-095219599
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160909-095219599
Official Citation:Remy,D., H. Perfettini,N.Cotte, J.P.Avouac, M. Chlieh, F. Bondoux, A. Sladen, H. Tavera, and A. Socquet (2016), Postseismic relocking of the subduction megathrust following the 2007 Pisco, Peru, earthquake, J. Geophys. Res. Solid Earth, 121, 3978–3995, doi:10.1002/2015JB012417
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:70231
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 Sep 2016 17:41
Last Modified:03 Nov 2016 20:06

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