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Shallow faults reactivated by hydraulic fracturing; the 2019 Weiyuan earthquake sequences in Sichuan, China

Wang Maomao, Yang Hongfeng, Fang Lihua, Han Libo, Jia Dong, Jiang Danqi and Yan Bing
Shallow faults reactivated by hydraulic fracturing; the 2019 Weiyuan earthquake sequences in Sichuan, China
Seismological Research Letters (November 2020) 91 (6): 3171-3181

Abstract

Human activity-induced earthquakes are emerging as a global issue, and revealing its underlying mechanisms is essential for earthquake hazard mitigation and energy development. We investigated the relationship between the seismotectonic model and seismic sequences from moderate M (sub w) 4.3 and M (sub w) 5.2 earthquakes that occurred in February and September 2019, respectively, in the Weiyuan anticline of Sichuan basin, China. We found that the M (sub w) 5.2 earthquake ruptured a back thrust of structural wedges and released most aftershocks near the wedge tip. However, the two foreshocks of the M (sub w) 4.3 earthquake sequence occurred in hydrofractured Silurian shale at depth of 2.5-3 km, and the mainshock ruptured the overlying oblique tear fault at a depth of approximately 1 km. Hydraulic fracturing in the sedimentary cover of this block may induce earthquakes through fluid pressure diffusion in the Silurian shale and through poroelastic effects on back thrusts within structural wedges, respectively. We assessed the hazard potential of four seismic sources in the Weiyuan block and suggest it is critical to conduct a coupled flow-geomechanics assessment and management on induced seismicity and related cascading effects in the densely inhabited and seismically active Sichuan basin.


ISSN: 0895-0695
EISSN: 1938-2057
Serial Title: Seismological Research Letters
Serial Volume: 91
Serial Issue: 6
Title: Shallow faults reactivated by hydraulic fracturing; the 2019 Weiyuan earthquake sequences in Sichuan, China
Affiliation: Hohai University, College of Oceanography, Nanjing, China
Pages: 3171-3181
Published: 202011
Text Language: English
Publisher: Seismological Society of America, El Cerrito, CA, United States
References: 47
Accession Number: 2021-006977
Categories: SeismologyStructural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables, sketch maps
N28°00'00" - N32°00'00", E102°00'00" - E106°00'00"
Secondary Affiliation: Chinese University of Hong Kong, CHN, ChinaChina Earthquake Administration, Institute of Geophysics, CHN, ChinaNanjing University, CHN, China
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2021, American Geosciences Institute. Abstract, Copyright, Seismological Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 202105
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