Patterns of Causative Faults of Normal Earthquakes in the Fluid-Rich Outer Rise of Northeastern Japan, Constrained With 3D Teleseismic Waveform Modeling

Qian, Yunyi1; Chen, Xiaofei2; Wu, Wenbo3; Wei, Shengji4; Ni, Sidao5; Xu, Min6; Qin, Yanfang7; Nakamura, Yasuyuki7; Zhou, Yong6; Sun, Daoyuan8

2024-06-01

10.1029/2024JB028740

JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH   影响因子和分区

2169-9313

2169-9356

Accurate earthquake source parameters are crucial for understanding plate tectonics, yet, it is difficult to determine these parameters precisely for offshore events, especially for outer-rise earthquakes, as the limited availability of direct P or S wave data sets from land-based seismic networks and the unsuitability of simplified 1D methods for the complex 3D structures of subducting systems. To overcome these challenges, we employ an efficient hybrid numerical simulation method to model these 3D structural effects on teleseismic P/SH and P-coda waves and determine the reliable centroid locations and focal mechanisms of outer-rise normal-faulting earthquakes in northeastern Japan. Two M6+ events with reliable locations from ocean bottom seismic observations are utilized to calibrate the 3D velocity structure. Our findings indicate that 3D synthetic waveforms are sensitive to both event location, thanks to bathymetry and water reverberation effects, and the shallow portion of the lithospheric structure. With our preferred velocity model, which has Versus similar to 16% lower than the global average, event locations are determined with uncertainties of <5 km for horizontal position and <1 km for depth. The refined event locations in a good match between one of the nodal strikes and the high-resolution bathymetry, enabling the determination of the causative fault plane. Our results reveal that trench-ward dipping normal faults are more active, with three parallel to the trench as expected, while five are associated with the abyssal hills. The significant velocity reduction in the uppermost lithosphere suggests abundant water migrating through active normal faults, enhancing both mineral alteration and pore density.

outer rise hydration waveform modeling normal fault earthquake source parameter inversion

SCI

英语

通讯

Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology[2022B1212010002] ; Guangdong Basic and Applied Basic Research Foundation[2021B1515020023] ; null[42104104]

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:001248022400001

AMER GEOPHYSICAL UNION

GEOSCIENCES

Web of Science

1.Chongqing Univ, Sch Resources & Safety Engn, State Key Lab Coal Mine Disaster Dynam & Control, Chongqing, Peoples R China
2.Southern Univ Sci & Technol, Dept Earth & Space Sci, Guangdong Prov Key Lab Geophys High Resolut Imagin, Shenzhen, Peoples R China
3.Woods Hole Oceanog Inst, Woods Hole, MA USA
4.Nanyang Technol Univ, Asian Sch Environm, Earth Observ Singapore, Singapore, Singapore
5.Chinese Acad Sci, Innovat Acad Precis Measurement Sci & Technol, State Key Lab Geodesy & Earths Dynam, Wuhan, Peoples R China
6.Chinese Acad Sci, South China Sea Inst Oceanol, Key Lab Ocean & Marginal Sea Geol, Guangzhou, Peoples R China
7.Japan Agcy Marine Earth Sci & Technol, Yokohama, Japan
8.Univ Sci & Technol China, Sch Earth & Space Sci, Hefei, Peoples R China

Qian, Yunyi,Chen, Xiaofei,Wu, Wenbo,et al. Patterns of Causative Faults of Normal Earthquakes in the Fluid-Rich Outer Rise of Northeastern Japan, Constrained With 3D Teleseismic Waveform Modeling[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,2024,129(6).

Qian, Yunyi.,Chen, Xiaofei.,Wu, Wenbo.,Wei, Shengji.,Ni, Sidao.,...&Sun, Daoyuan.(2024).Patterns of Causative Faults of Normal Earthquakes in the Fluid-Rich Outer Rise of Northeastern Japan, Constrained With 3D Teleseismic Waveform Modeling.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,129(6).

Qian, Yunyi,et al."Patterns of Causative Faults of Normal Earthquakes in the Fluid-Rich Outer Rise of Northeastern Japan, Constrained With 3D Teleseismic Waveform Modeling".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 129.6(2024).