Title: Aftershocks of the 2012 Off-Coast of Sumatra Earthquake Sequence

Abstract

Aftershocks of the 2012 Off-Coast of Sumatra Earthquake Sequence exhibit a complex and diffuse spatial distribution. The first-order complexity in aftershock distribution is clear and well beyond the influence of typical earthquake location uncertainty. The sequence included rupture of multiple fault segments, spatially separated. We use surface-wave based relative centroid locations to examine whether, at the small scale, the distribution of the aftershocks was influenced by location errors. Surface-wave based relative location has delineated precise oceanic transform fault earthquake locations in multiple regions. However, the relocated aftershocks off the coast of Sumatra seldom align along simple linear trends that are compatible with the corresponding fault strikes as estimated for the GCMT catalog. The relocation of roughly 60 moderate-earthquake epicentroids suggests that the faulting involved in the 2012 earthquake aftershock sequence included strain release along many short fault segments. Statistical analysis and temporal variations of aftershocks show a typical decay of the aftershocks but a relatively low number of aftershocks, as is common for intraplate oceanic earthquakes. Coulomb stress calculations indicate that most of the moderate-magnitude aftershocks are compatible with stress changes predicted by the large-event slip models. Furthermore the patterns in the aftershocks suggest that the formation of the boundarymore » and eventual localization of deformation between the Indian and Australian plate is a complicated process.« less

Authors:

Chai, Chengping  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-6792-6014"

Ammon, Charles J. ^[1]; Cleveland, Kenneth Michael  ^[2]

• Search DOE PAGES for author "Cleveland, Kenneth Michael"
• Search DOE PAGES for ORCID "0000-0001-5575-6372"

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+ Show Author Affiliations

1. The Pennsylvania State Univ., University Park, PA (United States)
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:

Fri May 10 00:00:00 EDT 2019

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1514982

Alternate Identifier(s):

OSTI ID: 1513402; OSTI ID: 1547204

Report Number(s):

LA-UR-18-28672
Journal ID: ISSN 0040-1951

Grant/Contract Number:  

89233218CNA000001; AC05-00OR22725

Resource Type:

Accepted Manuscript

Journal Name:

Tectonophysics

Additional Journal Information:

Journal Volume: 763; Journal Issue: C; Journal ID: ISSN 0040-1951

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

58 GEOSCIENCES; 2012 Sumatra Earthquake; Earthquake relocation; Aftershock analysis; Coulomb stress