scholarly journals Focal mechanism and seismogenic structure of the Shiqu MS4.4 earthquake1

2021 ◽  
pp. 100065
Author(s):  
Yang Yanming ◽  
Wang Shubo ◽  
Su riya
Keyword(s):  
Focal Mechanism ◽  
Seismogenic Structure

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.

EARTHQUAKE SOURCE PARAMETER AND FOCAL MECHANISM ESTIMATES FOR THE WESTERN QUEBEC SEISMIC ZONE IN EASTERN CANADA

2017 ◽  
Author(s):  
Alba M. Rodriguez Padilla ◽  
◽  
John Onwuemeka ◽  
John Onwuemeka ◽  
Yajing Liu ◽  
...  
Keyword(s):  
Focal Mechanism ◽  
Earthquake Source ◽  
Source Parameter ◽  
Seismic Zone ◽  
Eastern Canada

scholarly journals Stress relaxation arrested the mainshock rupture of the 2016 Central Tottori earthquake

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Yoshihisa Iio ◽  
Satoshi Matsumoto ◽  
Yusuke Yamashita ◽  
Shin’ichi Sakai ◽  
Kazuhide Tomisaka ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Focal Mechanism ◽  
Large Earthquake ◽  
Static Stress ◽  
Focal Mechanism Solutions ◽  
Large Earthquakes

AbstractAfter a large earthquake, many small earthquakes, called aftershocks, ensue. Additional large earthquakes typically do not occur, despite the fact that the large static stress near the edges of the fault is expected to trigger further large earthquakes at these locations. Here we analyse ~10,000 highly accurate focal mechanism solutions of aftershocks of the 2016 Mw 6.2 Central Tottori earthquake in Japan. We determine the location of the horizontal edges of the mainshock fault relative to the aftershock hypocentres, with an accuracy of approximately 200 m. We find that aftershocks rarely occur near the horizontal edges and extensions of the fault. We propose that the mainshock rupture was arrested within areas characterised by substantial stress relaxation prior to the main earthquake. This stress relaxation along fault edges could explain why mainshocks are rarely followed by further large earthquakes.

Focal mechanism solutions for roof collapse in deep mine

2015 ◽  
Vol 6 (1) ◽  
pp. 22
Author(s):  
Chun lai Wang ◽  
Hui Fu ◽  
Fu li Wang ◽  
Wei qiang Li ◽  
Ming Luo ◽  
...  
Keyword(s):  
Focal Mechanism ◽  
Deep Mine ◽  
Roof Collapse ◽  
Focal Mechanism Solutions

scholarly journals 2013 Seismic swarm recorded in Galati area, Romania: focal mechanism solutions

2016 ◽  
Vol 52 (1) ◽  
pp. 53-67 ◽  
Author(s):  
Andreea Craiu ◽  
Marius Craiu ◽  
Mihail Diaconescu ◽  
Alexandru Marmureanu
Keyword(s):  
Focal Mechanism ◽  
Focal Mechanism Solutions ◽  
Seismic Swarm

The Seismogenic Structure and Deformation Mechanism of the Lushan (Mw6.6) Earthquake, Sichuan, China

2016 ◽  
Vol 90 (2) ◽  
pp. 503-510
Author(s):  
ZHOU Rongjun ◽  
LI Yong ◽  
SHAO Chongjian ◽  
SU Jinrong ◽  
YAN Zhaokun ◽  
...  
Keyword(s):  
Deformation Mechanism ◽  
Seismogenic Structure
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