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Revisiting the 1992 Landers earthquake: a Bayesian exploration of co-seismic slip and off-fault damage

Gombert, B. and Duputel, Z. and Jolivet, R. and Doubre, C. and Rivera, L. and Simons, M. (2018) Revisiting the 1992 Landers earthquake: a Bayesian exploration of co-seismic slip and off-fault damage. Geophysical Journal International, 212 (2). pp. 839-852. ISSN 0956-540X. https://resolver.caltech.edu/CaltechAUTHORS:20180117-143004510

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Abstract

Existing models for the distribution of subsurface fault slip associated with the 1992 Landers, CA, earthquake (M_w = 7.3) show significant dissimilarities. In particular, they exhibit different amounts of slip at shallow depths (<5 km). These discrepancies can be primarily attributed to the ill-posed nature of the slip inversion problem and to the use of physically unjustifiable smoothing or regularization constraints. In this study, we propose a new coseismic model obtained from the joint inversion of multiple observations in a relatively unregularized and fully Bayesian framework. We use a comprehensive data set including GPS, terrestrial geodesy, multiple SAR interferograms and co-seismic offsets from correlation of aerial images. These observations provide dense coverage of both near- and far-field deformation. To limit the impact of modelling uncertainties, we develop a 3-D fault geometry designed from field observations, co-seismic offsets and the distribution of aftershocks. In addition, we account for uncertainty in the assumed elastic structure used to compute the Green’s functions. Our solution includes the ensemble of all plausible models that are consistent with our prior information and fit the available observations within data and prediction uncertainties. Using near-fault high-resolution ground deformation measurements and the density of aftershocks, we investigate the properties of the damage zone and its impact on the inferred slip at depth. We attribute a part of the inferred slip deficit at shallow depth to our models not including the impact of a damage zone associated with a reduction of shear modulus in the vicinity of the fault.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1093/gji/ggx455DOIArticle
https://academic.oup.com/gji/article/212/2/839/4561053PublisherArticle
ORCID:
AuthorORCID
Jolivet, R.0000-0002-9896-3651
Rivera, L.0000-0002-0726-5445
Simons, M.0000-0003-1412-6395
Additional Information:© 2017 The Authors. Published by Oxford University Press on behalf of The Royal Astronomical Society. Accepted 2017 October 17; Received 2017 October 16; in original form 2017 May 23; Published: 22 October 2017. We are grateful to J.P. Avouac and F. Ayoub for providing the optical images correlation observations. We also thank Y. Fialko for sending us his co-seismic slip model. This study contributed from fruitful discussions with Sarah Minson, Lijun Zhu, Michael Aivazis and Gilles Peltzer. Some GPUs used for this research were donated by the NVIDIA Corporation. This work was supported by the Initiative d’Excellence (IDEX) funding framework (Université de Strasbourg) and the CNRS PICS program (Zacharie Duputel). This work was also funded by NSF grant 1447107 awarded to Mark Simons. We thank the Editor, Martin Mai, and two anonymous reviewers for their constructive comments, which helped improve this manuscript.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
Université de StrasbourgUNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
NSFEAR-1447107
Subject Keywords:Inverse theory, Probability distributions, Earthquake source observations, Fractures, faults, and high strain deformation zones
Issue or Number:2
Record Number:CaltechAUTHORS:20180117-143004510
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20180117-143004510
Official Citation:B Gombert, Z Duputel, R Jolivet, C Doubre, L Rivera, M Simons; Revisiting the 1992 Landers earthquake: a Bayesian exploration of co-seismic slip and off-fault damage, Geophysical Journal International, Volume 212, Issue 2, 1 February 2018, Pages 839–852, https://doi.org/10.1093/gji/ggx455
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84367
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:17 Jan 2018 23:54
Last Modified:09 Mar 2020 13:19

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