Earthquake rupture dependence on hypocentral location along the Nicoya Peninsula subduction megathrust
Earthquake rupture dependence on hypocentral location along the Nicoya Peninsula subduction megathrust
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DOI：
10.1016/j.epsl.2019.05.030
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发表时间：
2019-08
影响因子：
5.3
通讯作者：
Hongfeng Yang;Suli Yao;B. He;A. Newman
中科院分区：
文献类型：
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作者：
Hongfeng Yang;Suli Yao;B. He;A. Newman
虽然震间锁定分布已被用于定性评估未来的地震潜力，定量估计地震如何可能通过锁定界面破裂是一个更有用的工具，量化地震和海啸的危险。在这里，我们调查破裂的情况下，从地震间锁定模型沿着的大型逆冲断层接口下面的尼科亚半岛，哥斯达黎加使用自发破裂模拟。我们首先估计初始应力锁定，然后启动自发破裂在不同的成核点，并观察最终的地震震级和滑动分布。根据现有的震间锁定模型，我们发现，在所测试的成核过程中，约有40%的成核过程发展为Mw> 7.2的大地震。在这些事件中，那些从更深的深度核有一个更大幅度的浅滑动的趋势，这表明增加海啸的潜力。此外，不考虑输入锁定模型，我们没有观察到6和7之间的中间震级的地震破裂的情况下，在尼科西亚的观测结果一致。与震源相关的地震震级和海啸发生潜力的研究结果不仅对通过闭锁模型估算破裂程度提出了挑战，而且强调了定量评估俯冲带地震和海啸危险性的重要性。
Although interseismic locking distributions have been used in qualitatively evaluating the future earthquake potential, quantitatively estimating how an earthquake may rupture through the locked interface is a more useful tool for quantifying both seismic and tsunami hazards. Here, we investigate rupture scenarios from interseismic locking models along the megathrust interface below Nicoya Peninsula, Costa Rica using spontaneous rupture simulations. We first estimate initial stress from locking, then initiate spontaneous ruptures at different nucleation points and observe the eventual earthquake magnitudes and slip distribution. We find that∼ 40% of nucleations tested develop into large earthquakes of M w> 7.2 based on present interseismic locking models. Of these events, those nucleated from deeper depths have a tendency for larger-amplitude shallow slip, suggesting increased tsunami potential. Furthermore, irrespective of the input locking models we do not observe rupture scenarios of earthquakes with intermediate magnitudes between 6 and 7, a result consistent with observations in Nicoya. The results of hypocentre-dependent earthquake magnitudes and tsunamigenic potential not only pose challenges in estimating rupture extents from locking models, but also underscore the significance of quantitatively evaluating seismic and tsunami hazard in subduction zones.