DYNAMIC SLIP TRANSFER FROM THE DENALI TO TOTSCHUNDA FAULTS, ALASKA: TESTING THEORY FOR FAULT BRANCHING
DYNAMIC SLIP TRANSFER FROM THE DENALI TO TOTSCHUNDA FAULTS, ALASKA: TESTING THEORY FOR FAULT BRANCHING
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DOI：
10.1785/0120040601
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发表时间：
2004-12
影响因子：
3
通讯作者：
H. Bhat;R. Dmowska;J. Rice;N. Kame
中科院分区：
文献类型：
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作者：
H. Bhat;R. Dmowska;J. Rice;N. Kame
我们分析了所观察到的动态滑动转移从德纳里Totschunda断层在MW 7.9 2002年11月3日德纳里断层地震，阿拉斯加。本研究采用了Poliakov等人（2002）和Kame等人（2003）的理论和方法，其中表明，破裂路径沿断层分支的倾向由预先存在的应力状态、分支角度和分支位置处的进入破裂速度决定。在这里，我们检查理论上的DenaliTotschunda破裂过程中使用的过程在附近的分支交界处的二维数值模拟。据估计，与交界处附近德纳里断层走向有关的最大压缩方向约为73 °至80 °。我们在数值模拟中使用70和80的值。分支处的破裂速度没有得到很好的限制，但估计在整个事件中平均约为0.8 cs。我们使用0.6 cs，0.8 cs，0.9 cs，甚至1.4 cs作为参数在我们的模拟。采用二维弹性动力学边界积分方程模型，模拟了具有沿着分支断层系统的自选路径的II型滑动弱化破裂的滑动传递。我们所有的模拟，除了70和0.9 cs预测，破裂路径分支的沿着Totschunda故障没有延续沿着德纳里故障。在这种特殊情况下，沿迪纳利断层沿着也有断裂延续，其速度比沿托特顺达断层沿着慢，滑动也较小。
We analyze the observed dynamic slip transfer from the Denali to Totschunda faults during the Mw 7.9 3 November 2002 Denali fault earthquake, Alaska. This study adopts the theory and methodology of Poliakov et al. (2002) and Kame et al. (2003), in which it was shown that the propensity of the rupture path to follow a fault branch is determined by the preexisting stress state, branch angle, and incoming rupture velocity at the branch location. Here we check that theory on the DenaliTotschunda rupture process using 2D numerical simulations of processes in the vicinity of the branch junction. The maximum compression direction with respect to the strike of the Denali fault near the junction has been estimated to range from approximately 73 to 80. We use the values of 70 and 80 in our numerical simulations. The rupture velocity at branching is not well constrained but has been estimated to average about 0.8 cs throughout the event. We use 0.6 cs, 0.8 cs, 0.9 cs, and even 1.4 cs as parameters in our simulations. We simulate slip transfer by a 2D elastodynamic boundary integral equation model of mode II slip-weakening rupture with self-chosen path along the branched fault system. All our simulations except for 70 and 0.9 cs predict that the rupture path branches off along the Totschunda fault without continuation along the Denali fault. In that exceptional case there is also continuation of rupture along the Denali fault at a speed slower than that along the Totschunda fault and with smaller slip.