Along-Strike Variation of Seismicity Near the Extinct Mid-Ocean Ridge Subducted Beneath the Manila Trench

Zhu, Gaohua1,2,3; Yang, Hongfeng3,4; Yang, Ting5; Zhang, Guangxu1,2

2023-03-01

10.1785/0220220304

SEISMOLOGICAL RESEARCH LETTERS   Impact Factor & Quartile

0895-0695

1938-2057

The change in seismic activity is explored using data recorded by ocean-bottom seismom-eters (OBSs) and permanent seismic stations near the extinct Mid-Ocean ridge of the South China Sea (SCS) and the Manila trench. We apply the machine learning-based algo-rithm EQTransformer to the OBS dataset for seismic event detection and phase picking and then evaluate the precision and compare the time residuals between automatic and manual picks. We derive a catalog of earthquakes in the region and find bending-fault earthquakes in the outer rise at the northern of the Huangyan (Scarborough) Seamount chain, where no historical seismicity was reported in the routine catalog. Abundant outer-rise earthquakes occurred on both sides of the Huangyan (Scarborough) Seamounts chain, but the focal depths vary along the trench. The Wadati-Benioff zone of the east-ward subducted SCS oceanic lithosphere can be clearly identified. The focal depths are down to-100 km near Luzon island at-16 degrees N but deepen southward to a depth of-180 km at-14 degrees N. Dips of the slab also steepen from north to south, indicating along-strike changes in the geometry of the Manila megathrust.

SCI

English

Others

National Natural Science Foundation of China["92158205","92058209","91958211"] ; Hong Kong Research Grant Council[14304820] ; Shenzhen Science and Technology Program["KQTD20170810111725321","JCYJ20180504170422082"] ; Youth Innovation Promotion Association Chinese Academy of Sciences Grant[2016189]

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:000944205000002

SEISMOLOGICAL SOC AMER

GEOSCIENCES

Web of Science

1.Chinese Acad Sci, Inst Oceanol, Ctr Ocean Mega Sci, CAS Key Lab Marine Geol & Environm, Qingdao, Peoples R China
2.Qingdao Natl Lab Marine Sci & Technol, Lab Marine Geol, Qingdao, Peoples R China
3.Chinese Univ Hong Kong, Fac Sci, Earth & Environm Sci Programme, Shatin, Hong Kong, Peoples R China
4.Chinese Univ Hong Kong, Shenzhen Res Inst, Shenzhen, Peoples R China
5.Southern Univ Sci & Technol, Dept Ocean Sci & Engn, OBS Lab, Shenzhen, Peoples R China

Zhu, Gaohua,Yang, Hongfeng,Yang, Ting,et al. Along-Strike Variation of Seismicity Near the Extinct Mid-Ocean Ridge Subducted Beneath the Manila Trench[J]. SEISMOLOGICAL RESEARCH LETTERS,2023,94(2A).

Zhu, Gaohua,Yang, Hongfeng,Yang, Ting,&Zhang, Guangxu.(2023).Along-Strike Variation of Seismicity Near the Extinct Mid-Ocean Ridge Subducted Beneath the Manila Trench.SEISMOLOGICAL RESEARCH LETTERS,94(2A).

Zhu, Gaohua,et al."Along-Strike Variation of Seismicity Near the Extinct Mid-Ocean Ridge Subducted Beneath the Manila Trench".SEISMOLOGICAL RESEARCH LETTERS 94.2A(2023).