Abstract

Research Article| April 03, 2019 The December 2018 ML 5.7 and January 2019 ML 5.3 Earthquakes in South Sichuan Basin Induced by Shale Gas Hydraulic Fracturing Xinglin Lei; Xinglin Lei aGeological Survey of Japan, AIST, Higashi 1‐1‐1, Tsukuba, Ibaraki 305‐8567, Japan, xinglin-lei@aist.go.jpzhiwei-wang@ies.ac.cn Search for other works by this author on: GSW Google Scholar Zhiwei Wang; Zhiwei Wang aGeological Survey of Japan, AIST, Higashi 1‐1‐1, Tsukuba, Ibaraki 305‐8567, Japan, xinglin-lei@aist.go.jpzhiwei-wang@ies.ac.cncAlso at State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, A1#, Hua Yan Li, Chaoyang District, Beijing 100029, China. Search for other works by this author on: GSW Google Scholar Jinrong Su Jinrong Su bEarthquake Monitoring Centre, Sichuan Earthquake Administration, Renming‐nan Road 3‐29, Chengdu 610041, China, sujr0816@163.com Search for other works by this author on: GSW Google Scholar Author and Article Information Xinglin Lei aGeological Survey of Japan, AIST, Higashi 1‐1‐1, Tsukuba, Ibaraki 305‐8567, Japan, xinglin-lei@aist.go.jpzhiwei-wang@ies.ac.cn Zhiwei Wang aGeological Survey of Japan, AIST, Higashi 1‐1‐1, Tsukuba, Ibaraki 305‐8567, Japan, xinglin-lei@aist.go.jpzhiwei-wang@ies.ac.cncAlso at State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, A1#, Hua Yan Li, Chaoyang District, Beijing 100029, China. Jinrong Su bEarthquake Monitoring Centre, Sichuan Earthquake Administration, Renming‐nan Road 3‐29, Chengdu 610041, China, sujr0816@163.com Publisher: Seismological Society of America First Online: 03 Apr 2019 Online Issn: 1938-2057 Print Issn: 0895-0695 © Seismological Society of America Seismological Research Letters (2019) 90 (3): 1099–1110. https://doi.org/10.1785/0220190029 Article history First Online: 03 Apr 2019 Connected Content Errata: The December 2018 ML 5.7 and January 2019 ML 5.3 Earthquakes in South Sichuan Basin Induced by Shale Gas Hydraulic Fracturing Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Xinglin Lei, Zhiwei Wang, Jinrong Su; The December 2018 ML 5.7 and January 2019 ML 5.3 Earthquakes in South Sichuan Basin Induced by Shale Gas Hydraulic Fracturing. Seismological Research Letters 2019;; 90 (3): 1099–1110. doi: https://doi.org/10.1785/0220190029 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search ABSTRACT An ML 5.7 earthquake struck Xingwen County, Sichuan Province, China (28.239° N, 104.922° E) on 16 December 2018. More than two weeks later on 3 January 2019, an ML 5.3 earthquake occurred 8 km to the west. These were the largest and most damaging events in the Changning shale gas block and resulted in extensive damage to nearby farmhouses and other structures. Although the official hypocentral depths for both events are large than 5 km, the centroid moment tensor solutions based on the generated cut‐and‐paste method were very shallow (3 and 1.8 km for ML 5.7 and 5.3, respectively). In addition, both events were very close to hydraulic‐fracturing (HF) zones of horizontal wells, in which HF was ongoing. A convening chain of evidence, including spatiotemporal correlation between earthquakes and HF zones, statistic parameters of seismicity, and estimated overpressure required to activate the unfavorably oriented source faults of the largest events, suggests that a series of earthquakes were induced by HF at a depth of ∼2.5–3 km⁠. In the Changning block, thus far, 11 ML≥4.0 events (including 3 ML≥5.0⁠) were observed since the systematic HF operation began in 2014. The Omori‐type aftershock productivity is very low as compared to normal tectonic seismicity. In addition, estimated overpressure ranged from ∼0.3 to 5.8 MPa for Mw>3.5 events. The poroelastic stress changes are less than 1 MPa out of the treatment zones. Hence, overpressure‐driven reactivation of pre‐existing faults (most of them are unmapped and unfavorably oriented for slip under the present tectonic stress field) is considered to be the cause of these abnormal moderate‐size earthquakes. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.