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Macrofracturing of Oceanic Lithosphere in Complex Large Earthquake Sequences

Lay, Thorne and Ye, Lingling and Wu, Zhenbo and Kanamori, Hiroo (2020) Macrofracturing of Oceanic Lithosphere in Complex Large Earthquake Sequences. Journal of Geophysical Research. Solid Earth, 125 (10). Art. No. e2020JB020137. ISSN 2169-9313. https://resolver.caltech.edu/CaltechAUTHORS:20200922-134833603

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Abstract

Major earthquakes in oceanic lithosphere seaward of the subduction zone outer trench slope are relatively uncommon, but several recent occurrences have involved very complex sequences rupturing multiple nonaligned faults and/or having high aftershock productivity with diffuse distribution. This includes the 21 December 2010 M_W 7.4 Ogasawara (Bonin), 11 April 2012 M_W 8.6 Indo‐Australia, 23 January 2018 M_W 7.9 Off‐Kodiak Island, and 20 December 2018 M_W 7.3 Nikol'skoye (northwest Pacific) earthquakes. Major oceanic intraplate event sequences farther from plate boundaries do not tend to be as complex in faulting or aftershocks. Outer trench slope extensional faulting can involve complex distributed sequences, particularly when activated by great megathrust ruptures such as 11 March 2011 M_W 9.1 Tohoku and 15 November 2006 M_W 8.3 Kuril Islands. Intense faulting sequences also occur near subduction zone corners, with many fault geometries being activated, including some in nearby oceanic lithosphere, as for the 29 September 2009 M_W 8.1 Samoa, 6 February 2013 M_W 8.0 Santa Cruz Islands, and 16 November 2000 M_W 8.0 New Ireland earthquakes. The laterally varying plate boundary stresses from heterogeneous locking, recent earthquakes, or boundary geometry influence the specific faulting geometries activated in nearby major intraplate ruptures in oceanic lithosphere. Preexisting lithospheric structures and fabrics exert secondary influences on the faulting. Intraplate stress release in oceanic lithosphere near subduction zones favors distributed macrofracturing of near‐critical fault systems rather than localized, single‐fault failures, both under transient loading induced by plate boundary ruptures and under slow loading by tectonic motions and slab pull.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1029/2020JB020137DOIArticle
http://wwweic.eri.u-tokyo.ac.jp/ETAL/KIKUCHIRelated ItemLeast squares inversion software
ORCID:
AuthorORCID
Lay, Thorne0000-0003-2360-4213
Ye, Lingling0000-0002-8739-2072
Wu, Zhenbo0000-0003-2894-2617
Kanamori, Hiroo0000-0001-8219-9428
Additional Information:© 2020 American Geophysical Union. Issue Online: 07 October 2020; Version of Record online: 07 October 2020; Accepted manuscript online: 09 September 2020; Manuscript accepted: 07 September 2020; Manuscript revised: 08 August 2020; Manuscript received: 05 May 2020. We thank Emily Brodsky for her thoughtful comments on the influence of plate boundary stress gradients. We appreciate helpful reviews from the JGR Editor R. Abercrombie, an anonymous reviewer, and C. Rollins. T. L.'s research on earthquakes is supported by U.S. National Science Foundation grant EAR1802364. L. Y.'s earthquake studies are supported by National Natural Science Foundation of China (41874056) and Fundamental Research Funds for the Central Universities, Sun Yat‐sen University (19lgzd11). Z. W. received support from Chengdu University of Technology and the National Natural Science Foundation of China (41704042). Data Availability Statement: All broadband seismic waveforms used in this study were accessed from the Data Management Center of the Incorporated Research Institutions for Seismology (https://www.iris.edu/hq/). Centroid moment‐tensor solutions were obtained from https://www.globalcmt.org/. Ocean bathymetry model ETOPO1 was obtained from NOAA (https://www.ngdc.noaa.gov/mgg/global/). The least squares inversion software is adapted from the package of Kikuchi and Kanamori (http://wwweic.eri.u-tokyo.ac.jp/ETAL/KIKUCHI/).
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFEAR-1802364
National Natural Science Foundation of China41874056
Fundamental Research Funds for the Central Universities19lgzd11
Sun Yat-sen UniverityUNSPECIFIED
Chengdu University of TechnologyUNSPECIFIED
National Natural Science Foundation of China41704042
Subject Keywords:oceanic intraplate earthquakes; outer rise faulting; complex earthquakes; plate stresses; earthquake productivity
Issue or Number:10
Record Number:CaltechAUTHORS:20200922-134833603
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200922-134833603
Official Citation:Lay, T., Ye, L., Wu, Z., & Kanamori, H. (2020). Macrofracturing of oceanic lithosphere in complex large earthquake sequences. Journal of Geophysical Research: Solid Earth, 125, e2020JB020137. https://doi.org/10.1029/2020JB020137
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105476
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:22 Sep 2020 20:59
Last Modified:20 Oct 2020 19:04

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