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Rupture Reactivation during the 2011 M_w 9.0 Tohoku Earthquake: Dynamic Rupture and Ground-Motion Simulations

Galvez, Percy and Dalguer, Luis A. and Ampuero, Jean-Paul and Giardini, Domenico (2016) Rupture Reactivation during the 2011 M_w 9.0 Tohoku Earthquake: Dynamic Rupture and Ground-Motion Simulations. Bulletin of the Seismological Society of America, 106 (3). pp. 819-831. ISSN 0037-1106. http://resolver.caltech.edu/CaltechAUTHORS:20160630-124120848

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Abstract

Near‐source ground‐motion observations and kinematic source inversions suggest that the rupture process of the 2011 M_w 9.0 Tohoku earthquake involved rupture reactivation, that is, repeated rupture nucleation in the same hypocentral area. This unusual phenomenon may have provided a second breath to the rupture that enhanced its final size. Here, we propose that rupture reactivation may have been governed by a slip‐weakening friction model with two sequential strength drops, the second one being activated at large slip. Such frictional behavior has been previously observed in laboratory experiments and attributed to pressurization of fault‐zone fluids by mineral decomposition reactions activated by shear heating, such as dehydration and decarbonation. Further evidence of this double‐slip‐weakening friction model is obtained here from the dynamic stress changes in the hypocentral region derived from a finite source inversion model. We incorporate this friction model in a dynamic rupture simulation comprising two main asperities constrained by source inversion models and several deep small asperities constrained by backprojection source imaging studies. Our simulation produces ground‐motion patterns along the Japanese coast consistent with observations and rupture patterns consistent with a kinematic source model featuring rupture reactivation. The deep small asperities serve as a bridge to connect the two main asperities, and the rupture reactivation mechanism is needed to reproduce the observed ground‐motion pattern. Therefore, we argue that rupture reactivation during the 2011 Tohoku earthquake is consistent with a second strength drop, possibly caused by activation of thermochemical weakening processes at large slip.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1785/0120150153DOIArticle
http://www.bssaonline.org/content/106/3/819PublisherArticle
http://bssa.geoscienceworld.org/content/106/3/819PublisherArticle
http://www.seismosoc.org/Publications/BSSA_html/bssa_106-3/2015153-esupp/index.htmlPublisherSupplementary Files
ORCID:
AuthorORCID
Ampuero, Jean-Paul0000-0002-4827-7987
Additional Information:© 2016 Seismological Society of America. Manuscript received 11 March 2016; Published Online 24 May 2016. This study was supported by the Quantitative Estimation of Earth’s Seismic Sources and Structure (QUEST) project funded by the Seventh Framework Programme of the European Commission, the Advanced Simulation of Coupled Earthquake and Tsunami Events (ASCETE) Project funded by the Volkswagen Foundation within the program “New Conceptual Approaches to Modeling and Simulation of Complex Systems,” and National Science Foundation (NSF) CAREER Award EAR‐1151926. We thank the Swiss project “High‐Rate GNSS for Seismology,” funded by the Swiss National Foundation, for providing us with the Global Positioning System (GPS) records of the GNSS Earth Observation Network System (GEONET). Simulations were done at the Swiss National Supercomputing Center (CSCS), under the production projects “Development of Dynamic Rupture Models to Study the Physics of Earthquakes and Near‐Source Ground Motion” and “Development of a Database of Physics‐Based Synthetic Earthquakes for Ground Motion Prediction.”
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
European CommissionUNSPECIFIED
Volkswagen FoundationUNSPECIFIED
NSFEAR-1151926
Swiss National Science Foundation (SNSF)UNSPECIFIED
Record Number:CaltechAUTHORS:20160630-124120848
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160630-124120848
Official Citation:Rupture Reactivation during the 2011 Mw 9.0 Tohoku Earthquake: Dynamic Rupture and Ground‐Motion Simulations Percy Galvez, Luis A. Dalguer, Jean‐Paul Ampuero, Domenico Giardini Bulletin of the Seismological Society of America Jun 2016, 106 (3) 819-831; DOI: 10.1785/0120150153
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:68787
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:06 Jul 2016 02:16
Last Modified:06 Jul 2016 02:16

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