Estimating rupture scenario likelihood based on dynamic rupture simulations: the example of the segmented Middle Durance fault, southeastern France
Estimating rupture scenario likelihood based on dynamic rupture simulations: the example of the segmented Middle Durance fault, southeastern France
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DOI：
10.1111/j.1365-246x.2006.02842.x
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发表时间：
2006-05
影响因子：
2.8
通讯作者：
H. Aochi;M. Cushing;O. Scotti;C. Berge-Thierry
中科院分区：
文献类型：
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作者：
H. Aochi;M. Cushing;O. Scotti;C. Berge-Thierry
摘要法国东南部的Middle Durance断层系统是一个缓慢活动的断层，它产生了中等规模的历史地震事件，并显示出在过去29000年中至少有一次Mw> 6.5事件的证据。动态破裂模拟的基础上，我们提出了地震的情况下，约束的构造应力场和3-D几何形状的耐久性断层系统的知识。用三维边界积分方程方法模拟了不同走向、倾角和倾角的断层段之间的动态破裂相互作用。对50种合理的应力场方向、应力场幅值和震源位置组合进行了试验。然后计算不同破裂演化的概率。每一段破裂主要是作为一个单一的事件（44%的50模拟测试在本文中）。然而，一个事件沿沿着三段同时触发的概率很高（26%），导致潜在破裂长度为45公里。最后，2%的模拟发生沿着四个相邻的部分，产生最大的总破裂长度为55公里。模拟结果表明，最南端最容易破裂（40%），因为它的构造应力方向有利，而且它的位置有利于与其他部分相互作用。与北行单向和双向传播模式相比，南行单向传播略受欢迎（41%）。虽然这些破裂情景不能直接转化为发生概率，但它们确实提供了更好的洞察力，可以更好地估计近场强地面运动和地震危险性。
SUMMARY The Middle Durance fault system, southeastern France, is a slow active fault that produced moderate-size historical seismic events and shows evidence of at least one M w > 6.5 event in the last 29 000 yr. Based on dynamic rupture simulation, we propose earthquake scenarios that are constrained by knowledge of both the tectonic stress field and of the 3-D geometry of the Durance fault system. We simulate dynamic rupture interaction among several fault segmentations of different strikes, dips and rakes, using a 3-D boundary integral equation method. 50 combinations of reasonable stress field orientations, stress field amplitudes and hypocentre locations are tested. The probability of different rupture evolutions is then computed. Each segment ruptures mainly as a single event (44 per cent of the 50 simulations test in this paper). However, the probability that an event triggers simultaneously along three segments is high (26 per cent), leading to a potential rupture length of 45 km. Finally, 2 per cent of the simulations occur along four adjacent segments, producing the greatest total rupture length of 55 km. The simulation results show that the southernmost segment is most easily ruptured (40 per cent), because of its favourable orientation with respect to the tectonic stress and of its favourable location for interaction with the other segments. South-bound unilateral propagation is slightly preferable (41 per cent), compared to north-bound unilateral and bilateral propagation modes. Although, these rupture scenarios cannot be directly translated into probabilities of occurrence, they do provide a better insight as to which rupture scenarios are more likely, an important element to better estimate near-field strong ground motion and seismic hazard.