Heterogeneous rupture on homogenous faults: Three‐dimensional spontaneous rupture simulations with thermal pressurization
Heterogeneous rupture on homogenous faults: Three‐dimensional spontaneous rupture simulations with thermal pressurization
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DOI：
10.1029/2008gl035577
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发表时间：
2008-11
影响因子：
5.2
通讯作者：
Y. Urata;K. Kuge;Y. Kase
中科院分区：
文献类型：
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作者：
Y. Urata;K. Kuge;Y. Kase
为了理解流体在地震破裂过程中的作用，我们通过计算矩形断层上的自发破裂传播，研究了热加压对动态破裂空间变化的影响。我们发现，即使在一个属性均匀的断层上，热加压也会导致破裂的不均匀性。在排水断层上，牵引力随滑动量的增加而线性下降，在任何地方都是一样的。然而，将排水条件改为不排水条件后，滑移弱化曲线变为非线性，并依赖于剪切带厚度w较小的断层上的位置，动摩擦应力随时间和空间变化。因此，当w较小时，超剪切过渡断层长度减小，最终滑移分布可能有一些峰值，与w无关，尤其是在不排水断层上。当震源区存在流体时，在确定动态破裂参数和模拟地震周期时应考虑这些影响。
To understand role of fluid on earthquake rupture processes, we investigated effects of thermal pressurization on spatial variation of dynamic rupture by computing spontaneous rupture propagation on a rectangular fault. We found thermal pressurization can cause heterogeneity of rupture even on a fault of uniform properties. On drained faults, tractions drop linearly with increasing slip in the same way everywhere. However, by changing the drained condition to an undrained one, the slip‐weakening curves become non‐linear and depend on locations on faults with small shear zone thickness w, and the dynamic frictional stresses vary spatially and temporally. Consequently, the super‐shear transition fault length decreases for small w, and the final slip distribution can have some peaks regardless of w, especially on undrained faults. These effects should be taken into account of determining dynamic rupture parameters and modeling earthquake cycles when the presence of fluid is suggested in the source regions.