Moment budget and seismic potential of the Xianshuihe-Xiaojiang fault system, southeastern Tibetan Plateau
Moment budget and seismic potential of the Xianshuihe-Xiaojiang fault system, southeastern Tibetan Plateau
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DOI：
10.1016/j.tecto.2023.229935
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发表时间：
2023-09
期刊：
影响因子：
2.9
通讯作者：
L. Yin;G. Luo;Mian Liu
中科院分区：
文献类型：
--
作者：
L. Yin;G. Luo;Mian Liu
鲜水河-小江断裂系是青藏高原东南部构造挤压模式中的重要边界断裂。它也是地震活跃，自1480年以来已经产生了7次M ≥ 7.5地震。我们编制了一个综合地震目录，以估计自1480年以来沿着XXFS的地震矩释放率，并将其与根据更新的GPS数据估计的矩累积进行比较。结果表明，XXFS的北方（鲜水河断裂）和中部（安和河-则木河-大凉山断裂）的矩亏损分别为2.49 × 1020 Nm和1.28 × 1020 Nm，分别相当于MW7.5和MW7.4事件的矩释放。另一方面，南部（小江断层）有力矩盈余，表明地震潜力相对较低。通过对断裂系统各段的力矩平衡分析，发现沿沿着XXFS存在6个力矩亏损段，包括炉霍段、乾宁-康定段、磨溪-安宁河段、安宁河-则木河断裂连接段、北方则木河段和则木河-小江断裂连接段。每一段的力矩不足都可能发生MW ≥ 6.5的事件，而乾宁-康定段则可能发生MW ≥ 7.4的事件。自1536年以来没有发生M ≥ 6.5事件的安宁河段也值得关注。
The Xianshuihe-Xiaojiang fault system (XXFS) is an important boundary fault in the model of tectonic extrusion in the southeastern Tibetan Plateau. It is also seismically active, having produced seven M ≥ 7.5 earthquakes since 1480 CE. We compiled an integrated earthquake catalog to estimate seismic moment release rates along the XXFS since 1480 CE, and compared them with moment accumulation estimated from the updated GPS data. Our results show moment deficits of ∼2.49 × 1020Nm for the northern (the Xianshuihe fault) and ∼ 1.28 × 1020Nm for the central (the Aninghe-Zemuhe-Daliangshan fault) parts of the XXFS, equivalent to the moment release of MW7.5 and Mw 7.4 events, respectively. The southern part (the Xiaojiang fault), on the other hand, has a moment surplus, suggesting a relatively low seismic potential. Analysis of moment budget on segments of the fault system indicates six sections of moment deficits along the XXFS, including the Luhuo segment, the Qanning-Kangding segment, the Moxi-Anninghe segment, the section connecting the Anninghe and Zemuhe faults, the northern Zemuhe segment and the connecting section between the Zemuhe and Xiaojiang faults. Each section of moment deficits could allow an MW∼ 6.5 event, whereas the Qianning-Kangding segment has the potential for an MW∼ 7.4 event. The Anninghe segment, where no M ≥ 6.5 event has occurred since 1536 CE, also deserves attention.