中国地震局杨光亮团队报道了青藏高原东北缘拉脊山断裂带地震应力演化的数值模拟。相关论文于2024年10月22日发表于《大地测量与地球动力学》杂志。

据介绍，本研究为分析历史地震对2023年积石山地震的触发关系，并估算震后邻近地区的地震危险性，评估了近百年来震源附近11次M_S（震级）≥6.0的地震，和1次5.7级的地震产生的地震应力演化过程。

结果表明，2023年积石山地震前，整个拉脊山北缘断裂带处于这12次地震产生的应力阴影下。2023年积石山地震震中应力减小量约为15.1kPa，该应力阴影的贡献主要来自1920年海原8.5级地震。震中的同震应力降为约292.1kPa， 2023年积石山地震的最大应力降为约346.2kPa。

积石山地震使拉脊山北缘断裂带两个震隙的应力分别增加了14.7kPa和59.7kPa，使拉脊山南缘断裂带的应力增加了10.9kPa，使循化南山断裂带东段的应力增加了11.1kPa。这些应力增量可能会提高这些断裂带的地震危险性。研究结果强调，在今后的防震减灾工作中，应重视这些断裂带的地震危险性。

附：英文原文

Title: Numerical simulation of seismic stress evolution in the Lajishan Fault zone on the northeastern margin of the Qinghai-Xizang Plateau

Author: Guangliang Yang a

Issue&Volume: 2024/10/22

Abstract: To analyze the triggering relationship of historical earthquakes to the 2023 Jishishan earthquake and estimate the seismic risk in the adjacent region after the earthquake, we calculate the evolution process of seismic stress generated by 11 earthquakes with M_S ≥ 6.0 and 1 earthquake with M_S5.7 near the source in the past 100 years. The results show that before the 2023 Jishishan earthquake, the entire Lajishan Northern Edge Fault zone was under the stress shadow generated by the 12 earthquakes. The stress reduction at the 2023 Jishishan earthquake epicenter was approximately 15.1 kPa, and the contribution of this stress shadow mainly comes from the 1920 M_S8.5 Haiyuan earthquake. The coseismic stress drop at the epicenter was around 292.1 kPa, and the maximum stress drop for the 2023 Jishishan earthquake was around 346.2 kPa. The Jishishan earthquake increased the stress of the two seismic gaps in the Lajishan Northern Edge Fault by 14.7 kPa and 59.7 kPa respectively, the stress on the Lajishan Southern Edge Fault zone increased by 10.9 kPa, and the stress on the east section of Xunhua Nanshan Fault increased by 11.1 kPa. These stress increments potentially elevate the seismic hazard along these fault zones. In the future earthquake prevention and disaster reduction, attention should be paid to the seismic risk of these fault zones.

DOI: 10.1016/j.geog.2024.09.005

Source: https://www.sciencedirect.com/science/article/pii/S1674984724001150