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1994年M_W=6.7的阿瑟山口地震的余震分布对于逆冲断层事件是不寻常的,其实际断层面沿NNW方向扩展了12 km,SSE方向扩展了30 km,走向为NE-SW。我们运用几种方法反推此区域的应力场,其中包括大地测量结果、地震震源机制结果,并用P波偏振数据反演了应力张量的方向。反演方法是新的,并不需要所用事件的震源机制,方法中也考虑了库仑破裂准则。所有结果均表明应力场支持走滑断层而不是逆断层。应力场中几乎水平的σ_1和σ_3主轴走向分别为298°和28°。运用位错理论,我们计算了阿瑟山口地震及其最大余震(走滑事件)诱发的应力并叠加到区域应力场中。远离主震断层面的余震位置与最优取向断层面上诱发的库仑破裂应力高值区域有很好的对应关系。然而,有一些高诱发库仑破裂应力的区域缺乏余震。与其他地方的观测一样,倾斜(19°)板块收敛区域的地震滑动可以分解为平行和垂直于板块边界的分量。像发生在太平洋板块和澳大利亚板块边界的右旋阿尔卑斯断层上那样,大部分滑动是平行的。然而,像阿瑟山口地震那样的偶尔的逆断层事件至少可以解释滑动的某些垂直分量和南阿尔卑斯隆起的形成。
The aftershock distribution of the Arthur’s Yamaguchi earthquake with M_W = 6.7 in 1994 is unusual for thrust events. Its actual fault plane extends 12 km in the NNW direction and extends 30 km in the SSE direction to NE-SW. We use several methods to deduce the stress field in this region, including the geodetic results and the earthquake focal mechanism results. The P-wave polarization data are used to invert the stress tensor direction. The inversion method is new and does not require the focal mechanism of the events used, and Coulomb failure criteria are also taken into account in the method. All the results show that the stress field supports strike-slip faults rather than reverse faults. The nearly horizontal horizontal directions of σ_1 and σ_3 in the stress field are 298 ° and 28 °, respectively. Using the dislocation theory, we calculate the stresses induced by the Aster Yamaguchi earthquake and its largest aftershock (slip event) and superimpose it into the regional stress field. The locations of aftershocks away from the fault surface of the main shock have a good correspondence with the areas of high Coulomb failure stress induced on the optimally oriented fault plane. However, there are few aftershocks in some areas where high Coulomb stress is induced. As observed elsewhere, seismic slips in the convergent (19 °) slab convergence zone can be decomposed into parallel and perpendicular components of the plate boundary. Like most of the dextral Alpine faults that occur at the Pacific and Australian plate boundaries, most of the slip is parallel. However, occasional reverse thrust events like the Arthur Pass earthquake explain at least some of the vertical component of slip and the formation of the Southern Alps uplift.