The 4 January 2020 offshore Pearl River Estuary earthquake sequence in South China: Implications for seismic potential of the NW-striking local faults

被引：0

作者：

Xia, Shaohong ^{[1
,4
]}

Lin, Jiangnan ^{[2
]}

Zhao, Dapeng ^{[3
]}

Cao, Jinghe ^{[1
]}

Zhang, Changrong ^{[1
]}

Wang, Xinyang ^{[1
]}

Wan, Kuiyuan ^{[1
]}

Fan, Chaoyan ^{[1
]}

机构：

[1] Chinese Acad Sci, South China Sea Inst Oceanol, CAS Key Lab Ocean & Marginal Sea Geol, Guangzhou 510301, Peoples R China

[2] Guangzhou Marine Geol Survey, Guangzhou 510075, Peoples R China

[3] Tohoku Univ, Grad Sch Sci, Dept Geophys, Sendai 9808578, Japan

[4] Southern Marine Sci & Engn Guangdong Lab Guangzhou, Guangzhou 511458, Peoples R China

来源：

JOURNAL OF ASIAN EARTH SCIENCES | 2023年 / 258卷

基金：

中国国家自然科学基金;

关键词：

Intraplate earthquake; Focal mechanism; 2020 Pearl River Estuary (PRE) Earthquake; Sequence; NW -striking local faults; Intersecting faults; South China sea; PLANE DETERMINATION; CRUSTAL STRUCTURE; STRAIN RATES; ZONE; GEOMETRY; STRESS; MODEL;

D O I：

10.1016/j.jseaes.2023.105697

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

The complexity of intraplate earthquakes and their challenge to current earthquake models persist as an important scientific and social problem, both about their causes and the resulting hazards. The Guangdong-Hong Kong-Macao Greater Bay area (GHMGB) is located in the coastal seismic zone of South China. Due to the huge residential population and important economic status, seismic hazard in the GHMGB often causes widespread concern. In this work, waveform data of the 2020 Pearl River Estuary (PRE) earthquake (ML3.5) and its aftershocks are carefully analyzed using about 6-month data recorded at 124 local seismic stations. A total of 8 aftershocks are identified. We determine the hypocentral parameters of the PRE mainshock and its aftershocks, as well as their focal mechanisms. Our results show that the 2020 PRE earthquake sequence is distributed in a NWSE direction with a lateral extent of about 3.5 km, which is consistent with the location of the NW-striking Qi'AoGuishan fault. The 2020 PRE earthquake and its aftershocks exhibit similar focal mechanisms. According to the stereographic projection results of the P and T axes, the orientation of the principal compressive stress is oblique to the NW-striking Qi'Ao-Guishan fault, hence these earthquakes are mainly characterized by left-lateral strikeslip faulting. In combination with many previous geological and geophysical results, we suggest that the NWstriking faults could have similar seismogenic importance as the NE-striking faults in the GHMGB and even the whole coast of the northern South China Sea, especially at the intersection of the NW- and NE-trending faults.

引用

页数：12