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Anomalously low aftershock productivity of the 2019 M_w 8.0 energetic intermediate-depth faulting beneath Peru

Ye, Lingling and Lay, Thorne and Kanamori, Hiroo (2020) Anomalously low aftershock productivity of the 2019 M_w 8.0 energetic intermediate-depth faulting beneath Peru. Earth and Planetary Science Letters, 549 . Art. No. 116528. ISSN 0012-821X. https://resolver.caltech.edu/CaltechAUTHORS:20200825-123111990

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Abstract

The 26 May 2019 Peru (M_W 8.0) earthquake struck within the nearly-horizontal underthrust Nazca plate at depths from ∼110 to 150 km below the upper Amazon, near a steep bend in the plate where it plunges down to a deep earthquake zone. Little prior seismicity occurred in this region, but large intraslab events with similar normal-faulting mechanisms have occurred to the west. The event is situated in a similar slab position to the 2017 Puebla-Morelos, Mexico earthquake, but the remote location resulted in limited loss of life and damage. Back-projection imaging and finite-fault inversion based on teleseismic data suggest a brittle and energetic rupture process with unilateral expansion northward over a 170-km-long zone at a rupture speed, V_r ∼3 km/s, with three normal-faulting patches of up to ∼4.5 m slip. Despite the mainshock size, it produced only three M4.0+ aftershocks within 300 km (one nearby); the aftershock productivity of the 2019 Peru earthquake is very low even among all large intermediate-depth earthquakes, but similar to that for other large Peruvian intraslab events. Comparison of aftershock productivity of the Peru event with that of global large earthquakes in various tectonic settings suggests that the low aftershock productivity can largely be attributed to regionally homogeneous faulting systems and relatively uniform stress state in the flat Peru slab.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.epsl.2020.116528DOIArticle
ORCID:
AuthorORCID
Ye, Lingling0000-0001-9689-4149
Lay, Thorne0000-0003-2360-4213
Kanamori, Hiroo0000-0001-8219-9428
Additional Information:© 2020 Published by Elsevier B.V. Received 16 March 2020, Revised 23 June 2020, Accepted 13 August 2020, Available online 25 August 2020. Teleseismic body wave waveforms were downloaded from the Incorporated Research Institutions for Seismology (IRIS) data management center (http://ds.iris.edu/wilber3/find_event). Global Centroid Moment Tensor Solutions are from https://www.globalcmt.org/CMTsearch.html. Aftershock analysis is based on the earthquake catalog from National Earthquake Information Center at U.S. Geological Survey (USGS-NEIC) (https://earthquake.usgs.gov/earthquakes/), last accessed in November 11, 2019. We thank Dr. Dan Sandiford, an anomalous reviewer and the editor Rebecca Bendick for their constructive review. K.D. Koper kindly provided his back-projection software. Lingling Ye's earthquake study is supported by National Natural Science Foundation of China (No. 41874056) and Fundamental Research Funds for the Central Universities, Sun Yat-sen University (No. 19lgzd11). Thorne Lay's earthquake research is supported by The National Science Foundation (Grant EAR1802364). CRediT authorship contribution statement: LY performed back-projection analysis and finite-fault inversion; HK conducted W-phase inversion; LY and TL designed aftershock productivity analysis; LY, TL and HK conceived the project, interpreted the result and wrote the manuscript collaboratively. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
National Natural Science Foundation of China41874056
Fundamental Research Funds for the Central Universities19lgzd11
NSFEAR-1802364
Subject Keywords:intermediate-depth earthquakes; 2019 Peru earthquake; aftershock productivity; flat slab; stress heterogeneity
Record Number:CaltechAUTHORS:20200825-123111990
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200825-123111990
Official Citation:Lingling Ye, Thorne Lay, Hiroo Kanamori, Anomalously low aftershock productivity of the 2019 MW 8.0 energetic intermediate-depth faulting beneath Peru, Earth and Planetary Science Letters, Volume 549, 2020, 116528, ISSN 0012-821X, https://doi.org/10.1016/j.epsl.2020.116528.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105102
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:25 Aug 2020 20:10
Last Modified:25 Aug 2020 20:10

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