The central segments of the Xianshuihe-Xiaojiang fault system (CSXXFS), which intersect densely populated areas, have remained seismically quiet without any strong earthquakes of M ≥ 7 for nearly two centuries. As such, conducting a comprehensive seismic hazard assessment of the CSXXFS serves as a crucial component of disaster mitigation efforts. To achieve this, we developed a finite element model that integrates heterogeneous mechanical properties constrained by interseismic deformation to estimate the fault locking depths within the CSXXFS. Subsequently, we performed an analysis of the seismic moment budget and Coulomb stress change to comprehensively assess the seismic hazards in the vicinity of the CSXXFS. Our findings revealed an overall average locking depth of 10 km for the Xianshuihe-Xiaojiang fault system (XXFS) and 15 km for the Daliangshan fault (DLSF). The discrepancy between the seismogenic depth and the fault locking depth indicates the presence of deep creep in certain segments of the CSXXFS. Additionally, historical earthquakes have caused stress modulation, resulting in potential earthquakes being either delayed or advanced in different segments of the CSXXFS. Specifically, the future seismic hazard is delayed in the entire Zemuhe fault (ZMHF), the northern segment of the Anninghe fault (ANHF), the southern section of the Shimian-Yuexi segment of the north Daliangshan fault (NDLSF), and the southernmost part of the south Daliangshan fault (SDLSF). Conversely, the potential earthquake on the Mianning-Xichang segment of the ANHF and the majority of the DLSF have been advanced due to positive earthquake-induced stress. Our estimation of the seismic budget suggests that the ANHF, ZMHF, NDLSF, and SDLSF have the potential to host earthquakes with magnitudes of M 6.9, M 7.3, M 7.4, and M 7.1, respectively. By adopting this integrated seismic hazard analysis, we highlight the necessity of closely evaluating potential risks and implementing appropriate mitigation strategies in this area.

中文翻译：

---

鲜水河-小江断裂系中段应力演化和地震矩预算的数值模拟：对地震危险性评估的启示


鲜水河-小江断裂系（CSXXFS）的中段与人口密集区相交，近两个世纪以来一直保持地震平静，没有发生过 7 级以上的强震。因此，对 CSXXFS 进行全面的地震灾害评估是减灾工作的重要组成部分。为了实现这一目标，我们开发了一个有限元模型，该模型集成了受震间变形约束的异质力学特性，以估计 CSXXFS 内的断层锁定深度。随后，我们对地震矩预算和库仑应力变化进行了分析，以综合评估CSXXFS附近的地震危险性。我们的研究结果显示，鲜水河-小江断裂带 (XXFS) 的总体平均锁定深度为 10 公里，大凉山断裂带 (DLSF) 的总体平均锁定深度为 15 公里。发震深度与断层锁定深度之间的差异表明CSXXFS某些段存在深层蠕变。此外，历史地震引起了应力调制，导致 CSXXFS 不同部分的潜在地震延迟或提前。具体而言，未来地震危险性在整个则木河断裂带（ZMHF）、安宁河断裂带北段（ANHF）、大凉山北断层石棉-岳西段南段（NDLSF）和最南端大凉山南断裂带（SDLSF）。相反，ANHF 冕宁—西昌段和大部分 DLSF 的潜在地震由于正震诱发应力而提前。 我们对地震预算的估计表明，ANHF、ZMHF、NDLSF 和 SDLSF 可能分别发生 6.9 级、7.3 级、7.4 级和 7.1 级地震。通过采用这种综合地震灾害分析，我们强调了密切评估潜在风险并在该地区实施适当缓解策略的必要性。