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ISSN 2096-7780 CN 10-1665/P

环文林, 张萌, 潘华. 四川康定—磨西断裂强震危险背景研究[J]. 地震科学进展 . DOI: 10.19987/j.dzkxjz.2023-008
引用本文: 环文林, 张萌, 潘华. 四川康定—磨西断裂强震危险背景研究[J]. 地震科学进展 . DOI: 10.19987/j.dzkxjz.2023-008
Huan Wenlin, Zhang Meng, Pan Hua. Study on the risk background of strong earthquake in Kangding-Moxi fault, Sichuan[J]. Progress in Earthquake Sciences. DOI: 10.19987/j.dzkxjz.2023-008
Citation: Huan Wenlin, Zhang Meng, Pan Hua. Study on the risk background of strong earthquake in Kangding-Moxi fault, Sichuan[J]. Progress in Earthquake Sciences. DOI: 10.19987/j.dzkxjz.2023-008

四川康定—磨西断裂强震危险背景研究

Study on the risk background of strong earthquake in Kangding-Moxi fault, Sichuan

  • 摘要: 本文对四川西部鲜水断裂带上的康定—磨西断裂的强震危险性作了分析探讨。该断裂位于川西—滇东第Ⅲ弧形挤出构造带的弧顶转折部位,这里应力高度集中,块体左旋大幅度滑移,断裂两侧垂直差异运动幅度达1000~2000 m。为大陆板块内部断裂活动性较高的地震区。鲜水河断裂带是我国地震活动性和重复性都很高的一条左旋走滑断裂带,自1725年至今接近300年的时间里,鲜水河断裂带上重复出现了两期地震活动,地震重复周期为100~200年。康定—磨西断裂于1786年发生过7¾级大地震,此地震发生迄今已237年,断裂一直处于能量积累的相对平静期。近期地震活跃起来,2022年9月6.8级四川沪定磨西镇地震以后5.6级以下的中小震频繁发生,并沿着磨西断裂成带分布,是否预示着该断裂又重新活动起来,进入新的地震活动期?这些特征表明康定—磨西断裂具有大地震孕育发生的背景条件。

     

    Abstract: In this paper, the strong earthquake risk of the Kangding-Moxi fault on the Xianshui fault zone in western Sichuan is analyzed and discussed. The fault is located at the arc top turning point of the third arc extrusion structural belt from western Sichuan to eastern Yunnan, where the stress is highly concentrated, the block has a large left-lateral slip, and the range of vertical differential movement between the two sides of the fault is up to 1000-2000 m. It is a seismic area with high fault activity within the continental plate. The Xianshuihe fault zone is a left-lateral strike-slip fault zone with high seismicity and repeatability in China. In the nearly 300 years since 1725, two periods of seismicity have repeatedly occurred on the Xianshuihe fault zone, and the earthquake repetition period is 100~200 years. The Kangding-Moxi fault occurred a large earthquake of magnitude 7¾ in 1786. It has been 237 years since the earthquake occurred, and the fault has been in a relatively quiet period of energy accumulation. Recent earthquakes have become active. After the M6.8 Moxi Town earthquake in Huding, Sichuan Province in September 2022, medium and small earthquakes with M < 5.6 occurred frequently and distributed along the Moxi fault, does it indicate that the fault is active again and enters a new seismicity period? These characteristics indicate that the Kangding-Moxi fault has the background conditions for the occurrence of large earthquakes.

     

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