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利用2001年昆仑山口西MS8.1地震现场观测所提供的地表破裂同震位移数据,使用简单滑移弱化破裂模型,估算了发震主断层上的破裂传播速度.该模型中考虑了断层破裂时动摩擦过程中应力上调和下调机制对地震波辐射能量分配的影响.对比Bouchon和Vallée有关昆仑山口西地震主断层破裂传播速度超过剪切波速度,甚至达到P波速度的结果,采用动摩擦应力下调时的滑移弱化模型(分数应力降模型),结果表明,伴随较高的地震波辐射效率,主断层的平均破裂传播速度等于或小于瑞利波速度,这与许力生和陈运泰的体波反演结果,以及陈学忠震源应力场估算的结果是一致的.最后,联系到由地表破裂现象所反映出的断层力学特征,如与视应力相关的分数应力降(动摩擦应力下调),基于滑移弱化模型,讨论了可能的震源破裂机制.
Based on the data of the surface rupture and coseismic displacements provided by the on-site observation of the Kunlun Mountain Pass MS8.1 earthquake in 2001, the rupture propagation velocity of the main fault is estimated by using the simple slip weakening rupture model. In this model, the fault rupture The effect of Bouchon and Vallée on the main fault rupture propagation velocity of the West Kunlun Mountain Pass earthquake exceeds the shear wave velocity and reaches the result of P-wave velocity. When the dynamic friction stress is down The results show that the average rupture propagation velocity of the main fault with the higher seismic radiation efficiency is equal to or less than the Rayleigh wave velocity. This is consistent with the results of body-wave inversion of Xu Lisheng and Chen Yuntai, and Chen Xuezhong The results of the source stress field estimation are consistent.Finally, the fracture mechanics characteristics reflected by surface rupture, such as the fractional stress drop related to visual stress (dynamic friction stress reduction), are discussed. Based on the slip weakening model, Possible source rupture mechanism.