Joint analysis of the 2014 Kangding, southwest China, earthquake sequence with seismicity relocation and InSAR inversion

2015 ◽  
Vol 42 (9) ◽  
pp. 3273-3281 ◽  
Author(s):  
Guoyan Jiang ◽  
Yangmao Wen ◽  
Yajing Liu ◽  
Xiwei Xu ◽  
Lihua Fang ◽  
...  
Keyword(s):  
Southwest China ◽  
Earthquake Sequence ◽  
Joint Analysis ◽  
China Earthquake

scholarly journals Focal Mechanism and Seismogenic Structure of the MS 5.1 Qingbaijiang Earthquake on February 3, 2020, Southwestern China

2021 ◽  
Vol 9 ◽  
Author(s):  
Min Zhao ◽  
Feng Long ◽  
Guixi Yi ◽  
MingJian Liang ◽  
Jiangtao Xie ◽  
...  
Keyword(s):  
Fault Zone ◽  
Focal Mechanism ◽  
Earthquake Sequence ◽  
Southwestern China ◽  
Joint Analysis ◽  
Focal Mechanism Solution ◽  
Inversion Method ◽  
Seismogenic Structure ◽  
Initial Rupture ◽  
Hypocentral Distribution

The 3 February 2020 MS 5.1 Qingbaijiang earthquake, southwestern China, is the closest recorded MS ≥ 5.0 event to downtown Chengdu City to date, with an epicentral distance of only 38 km. Here we analyze seismic data from the Sichuan and Chengdu regional seismic networks, and employ a multi-stage location method to relocate the earthquakes that have occurred along the central and northern segments of the Longquanshan fault zone since 2009, including the MS 5.1 Qingbaijiang earthquake sequence, to investigate the seismogenic structure of the region. The relocation results indicate that the seismicity along the central and northern segments of the Longquanshan fault zone has occurred mainly along the eastern branch since 2009, with the hypocentral distribution along a vertical cross-section illustrating a steep, NW-dipping parallel imbricate structure. The terminating depth of the eastern branch is about 12 km. The distribution of the MS 5.1 Qingbaijiang earthquake sequence is along the NE–SW-striking Longquanshan fault zone. The aftershock focal depths are in the 3–6 km range, with the mainshock located at 104.475°E, 30.73°N. Its initial rupture depth of 5.2 km indicates that the earthquake occurred above the shallow decollement layer of the upper crust in this region. The hypocentral distribution along the long axis of the aftershock area highlights that this earthquake sequence occurred along a fault dipping at 56° to the NW. Our surface projection of the inferred fault plane places it near the eastern branch of the Longquanshan fault zone. We infer the MS 5.1 mainshock to be a thrust faulting event based on the focal mechanism solution via the cut-and-paste waveform inversion method, with strike/dip/rake parameters of 22°/36°/91° and 200°/54°/89° obtained for nodal planes I and II, respectively. We identify that the seismogenic fault of the MS 5.1 Qingbaijiang earthquake lies along the eastern branch of the Longquanshan fault zone, and nodal plane II represents the coseismic rupture plane, based on a joint analysis of the event relocation results, mainshock focal mechanism, and regional geological information. Our study provides vital information for assessing the seismic hazard of the Longquanshan fault zone near Chengdu City.

scholarly journals Hazard Implications of the 2016 Mw 5.0 Cushing, OK Earthquake from a Joint Analysis of Damage and InSAR Data

2018 ◽  
Vol 10 (11) ◽  
pp. 1715 ◽  
Author(s):  
Magali Barba-Sevilla ◽  
Bridger Baird ◽  
Abbie Liel ◽  
Kristy Tiampo
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Critical Infrastructure ◽  
European Space Agency ◽  
Significant Risk ◽  
Surface Displacement ◽  
Earthquake Sequence ◽  
Joint Analysis ◽  
Oil Storage ◽  
The Impact

The Cushing Hub in Oklahoma, one of the largest oil storage facilities in the world, is federally designated as critical national infrastructure. In 2014, the formerly aseismic city of Cushing experienced a Mw 4.0 and 4.3 induced earthquake sequence due to wastewater injection. Since then, an M4+ earthquake sequence has occurred annually (October 2014, September 2015, November 2016). Thus far, damage to critical infrastructure has been minimal; however, a larger earthquake could pose significant risk to the Cushing Hub. In addition to inducing earthquakes, wastewater injection also threatens the Cushing Hub through gradual surface uplift. To characterize the impact of wastewater injection on critical infrastructure, we use Differential Interferometric Synthetic Aperture Radar (DInSAR), a satellite radar technique, to observe ground surface displacement in Cushing before and during the induced Mw 5.0 event. Here, we process interferograms of Single Look Complex (SLC) radar data from the European Space Agency (ESA) Sentinel-1A satellite. The preearthquake interferograms are used to create a time series of cumulative surface displacement, while the coseismic interferograms are used to invert for earthquake source characteristics. The time series of surface displacement reveals 4–5.5 cm of uplift across Cushing over 17 months. The coseismic interferogram inversion suggests that the 2016 Mw 5.0 earthquake is shallower than estimated from seismic inversions alone. This shallower source depth should be taken into account in future hazard assessments for regional infrastructure. In addition, monitoring of surface deformation near wastewater injection wells can be used to characterize the subsurface dynamics and implement measures to mitigate damage to critical installations.

Preliminary Report on the 3 August 2014, Mw 6.2/Ms 6.5 Ludian, Yunnan-Sichuan Border, Southwest China, Earthquake

2015 ◽  
Vol 86 (3) ◽  
pp. 750-763 ◽  
Author(s):  
J. Cheng ◽  
Z. Wu ◽  
J. Liu ◽  
C. Jiang ◽  
X. Xu ◽  
...  
Keyword(s):  
Preliminary Report ◽  
Southwest China ◽  
China Earthquake

scholarly journals Relocation of the 10 March 2011 Yingjiang, China, earthquake sequence and its tectonic implications

2012 ◽  
Vol 25 (1) ◽  
pp. 103-110 ◽  
Author(s):  
Jianshe Lei ◽  
Guangwei Zhang ◽  
Furen Xie ◽  
Yuan Li ◽  
Youjin Su ◽  
...  
Keyword(s):  
Earthquake Sequence ◽  
Tectonic Implications ◽  
China Earthquake

scholarly journals Characteristics of long-term regional seismicity before the 2008 Wen-Chuan, China, earthquake using pattern informatics and genetic algorithms

2011 ◽  
Vol 11 (3) ◽  
pp. 1003-1009 ◽  
Author(s):  
H.-C. Li ◽  
C.-C. Chen
Keyword(s):  
Genetic Algorithms ◽  
Earthquake Sequence ◽  
Seismic Precursors ◽  
Regional Seismicity ◽  
Pattern Informatics ◽  
China Earthquake ◽  
Relationship Of ◽  
Seismic Anomaly ◽  
Taiwan Earthquake

Abstract. To understand the generation of the 2008 Wen-chuan, China earthquake, we developed a strategy to objectively identify possible seismic precursors. Based on the pattern informatics (PI) method, the pattern of seismic anomaly was identified by the aid of genetic algorithms (GA) to be highly similar to the spatial distribution of the Wen-chuan earthquake sequence. We found that smaller earthquakes (M < 4.4) showed a linear relationship of Gutenberg-Richter (G-R) distribution. However, the frequency of the intermediate earthquakes (M ≥ 4.4) showed an uplift. This uplift supports the seismic activation hypothesis developed by Rundle et al. (2000b) and is similar to the case of the 1999 Chi-chi, Taiwan earthquake sequence reported by Chen (2003).

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