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<p>The Sichuan-Yunnan region hosts numerous large active faults with complex spatial distributions and intricate intersections, where moderate-to-strong earthquakes occur frequently. Obtaining source mechanism solutions for these earthquakes is not only essential for analyzing the regional crustal stress regime, fault geometries, activity behaviors and seismic potentials, but also is critical for assessing seismic hazards. Previous studies have obtained source mechanism catalogs of regional historical moderate-to-strong earthquakes based on 1D crustal velocity models, or inverted source mechanisms for few representative events based on 3D velocity models incorporating lateral variations. However, a systematic source mechanism inversion framework, which integrates regional high-resolution 3D velocity models with significant topographic relief, still remains absent for the Sichuan-Yunnan region. Using the high-resolution 3D velocity model SWChinaCVM-2.0 with regional topographic relief, we first construct a comprehensive strain Green’s tensor library for the 181 permanent broadband seismic stations across the Sichuan-Yunnan region. In particular, the forward modeling employs the spectral element method (SEM) with source-receiver reciprocity, followed by highly efficient compression of the computed library. Subsequently, a systematic source mechanism inversion is conducted for the 563 <i>M</i><sub>L</sub>⩾4 earthquakes occurring in the region during 2009–2021 using full waveform matching. With the derived solutions of fault planes, full moment tensors and moment magnitudes, a new-generation, accurate source mechanism catalog for moderate-to-strong earthquakes in the Sichuan-Yunnan region is obtained. This catalog can provide essential data for future geoscience studies in the Sichuan-Yunnan region, and is a foundational geophysical work driven by new techniques and methods. In the future, the inversion framework can also be applied to areas with high seismic risks such as North China and Xinjiang, providing essential supports for rapid and accurate determination of source parameters and assessment of seismic hazards.</p>

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A new-generation source mechanism catalogue for historical moderate-to-strong earthquakes in the Sichuan-Yunnan region constrained by a topographic high-resolution 3D velocity model and seismic waveform matching

  • 期刊论文

  • 发表日期：

    2025年11月11日

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  • Chang Guo,
  • Junlun Li,
  • Weiwei Wu,
  • Huajian Yao

摘要

The Sichuan-Yunnan region hosts numerous large active faults with complex spatial distributions and intricate intersections, where moderate-to-strong earthquakes occur frequently. Obtaining source mechanism solutions for these earthquakes is not only essential for analyzing the regional crustal stress regime, fault geometries, activity behaviors and seismic potentials, but also is critical for assessing seismic hazards. Previous studies have obtained source mechanism catalogs of regional historical moderate-to-strong earthquakes based on 1D crustal velocity models, or inverted source mechanisms for few representative events based on 3D velocity models incorporating lateral variations. However, a systematic source mechanism inversion framework, which integrates regional high-resolution 3D velocity models with significant topographic relief, still remains absent for the Sichuan-Yunnan region. Using the high-resolution 3D velocity model SWChinaCVM-2.0 with regional topographic relief, we first construct a comprehensive strain Green’s tensor library for the 181 permanent broadband seismic stations across the Sichuan-Yunnan region. In particular, the forward modeling employs the spectral element method (SEM) with source-receiver reciprocity, followed by highly efficient compression of the computed library. Subsequently, a systematic source mechanism inversion is conducted for the 563 ML⩾4 earthquakes occurring in the region during 2009–2021 using full waveform matching. With the derived solutions of fault planes, full moment tensors and moment magnitudes, a new-generation, accurate source mechanism catalog for moderate-to-strong earthquakes in the Sichuan-Yunnan region is obtained. This catalog can provide essential data for future geoscience studies in the Sichuan-Yunnan region, and is a foundational geophysical work driven by new techniques and methods. In the future, the inversion framework can also be applied to areas with high seismic risks such as North China and Xinjiang, providing essential supports for rapid and accurate determination of source parameters and assessment of seismic hazards.