FocMech-Flow: Automatic Determination of P-Wave First-Motion Polarity and Focal Mechanism Inversion and Application to the 2021 Yangbi Earthquake Sequence
Source abstract
Abstract
P-wave first-motion polarity is important for the inversion of earthquake focal mechanism solutions. The focal mechanism solution can further contribute to our understanding of the source rupture process, the fault structure, and the regional stress field characteristics. By using the abundant focal mechanism solutions of small and moderate earthquakes, we can deepen our understanding of fault geometry and the seismogenic environment. In this paper, we propose an automatic workflow, FocMech-Flow (Focal Mechanism-Flow), for identifying P-wave first-motion polarity and focal mechanism inversion with deep learning and applied it to the 2021 Yangbi earthquake sequence. We use a deep learning model named DiTingMotion to detect the P-wave first-motion polarity of 2389 waveforms, resulting in 98.49% accuracy of polarity discrimination compared with human experts. The focal mechanisms of 112 earthquakes are obtained by using the CHNYTX program, which is 3.7 times more than that of the waveform inversion method, and the results are highly consistent. The analysis shows that the focal mechanisms of the foreshock sequence of the Yangbi earthquake are highly consistent and are all of the strike-slip type; the focal mechanisms of the aftershock sequence are complex, mainly the strike-slip type, but there are also reverse and normal fault types. This study shows that the deep learning method has high reliability in determining the P-wave first-motion polarity, and FocMech-Flow can obtain a large number of focal mechanism solutions from small and moderate earthquakes, having promising application in fine-scale stress inversion.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Seismology and Earthquake Studies · earthquake and tectonic studies · Earthquake Detection and Analysis
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
Key Laboratory of Earthquake Source Physics, China Earthquake Administration, Beijing 100081, China
Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
Department of Earth and Planetary Sciences, University of California, Riverside, CA 92521, USA
Fujian Earthquake Agency, Fuzhou 350003, China
Funding
National Key R & D Plan · Basic Research Project of the Institute of Geophysics, China Earthquake Administration
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