Constraint of fault parameters inferred from nonplanar fault modeling
Constraint of fault parameters inferred from nonplanar fault modeling
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非平面断层建模推断的断层参数约束
DOI：
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发表时间：
2003
期刊：
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通讯作者：
E. Fukuyama
中科院分区：
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作者：
H. Aochi;R. Madariaga;E. Fukuyama
本文通过动态破裂模拟研究了1992年6月28日加州兰德斯地震的初始应力和摩擦参数沿沿着非平面断层系统的分布。我们发现，地表附近的大滑移分布的观测证据需要大的非零凝聚力的深度相关的摩擦定律。这是压力能够在浅深度积累和释放的唯一方式。然后，我们研究了沿断层走向的摩擦参数的变化沿着。为此，我们将Peyrat等人[2001]使用平面断层模型反演的初始应力不均匀性映射到分段断层模型中。与此初始应力场的模拟提高了整体适合的破裂过程中推断的运动反演，也提高了适合在南加州观察到的地面运动。为了获得这种拟合，我们必须引入沿断层沿着的摩擦参数的附加变化。最重要的是一个弱基卡普断层和一个强约翰逊谷断层。
We study the distribution of initial stress and frictional parameters for the 28 June 1992 Landers, California, earthquake through dynamic rupture simulation along a nonplanar fault system. We find that observational evidence of large slip distribution near the ground surface requires large nonzero cohesive forces in the depth‐dependent friction law. This is the only way that stress can accumulate and be released at shallow depths. We then study the variation of frictional parameters along the strike of the fault. For this purpose we mapped into our segmented fault model the initial stress heterogeneity inverted by Peyrat et al. [2001] using a planar fault model. Simulations with this initial stress field improved the overall fit of the rupture process to that inferred from kinematic inversions, and also improved the fit to the ground motion observed in Southern California. In order to obtain this fit, we had to introduce an additional variations of frictional parameters along the fault. The most important is a weak Kickapoo fault and a strong Johnson Valley fault.