Dynamics of Dip-Slip Fault Rupture
Dynamics of Dip-Slip Fault Rupture
复制标题
倾滑断层破裂动力学
DOI：
10.1088/1755-1315/861/4/042085
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
K.
中科院分区：
文献类型：
--
作者：
Uenishi;K.
这一贡献总结了我们最近关于浅层倾滑地震动力学，特别是挂墙和下盘不对称地震运动的研究成果。首先，通过实验动态光弹性和有限差分数值模拟，研究了自由面附近较大断层面的动态破裂。例如，在原生向上断层破裂的表面上，可以诱导出向外传播到远场的瑞利面波和向下向下移动到震源的瑞利型界面波。对于倾斜的断层面，这些瑞利波和界面波可以在上盘相互作用，产生能量集中的“角”横波，从而产生不对称地震运动。然后，不再只考虑单一的大型断裂面，而是研究了几何上更复杂的倾滑断层，这些断层由具有较小规模的平行裂隙的损伤区组成。光弹研究表明，根据倾角的不同，断裂行为可能会有很大的不同。对于较大的倾角，即使没有额外的外部载荷，二次和进一步的向下破裂也可以被启动、阻止和恢复动态运动，这似乎是由于初级向上破裂引起的动态波动。
This contribution summarizes our recent findings related to the dynamics of shallow dip-slip earthquakes, especially that of the asymmetric seismic motion in hanging walls and footwalls. First, by means of experimental dynamic photoelasticity and numerical finite difference simulations, dynamic rupture of a relatively large fault plane near a free surface is studied. It is found, for instance, that upon surfacing of the primary upward fault rupture, Rayleigh surface waves traveling outwards to the far-field and Rayleigh-type interface waves moving downwards back to the source can be induced. For an inclined fault plane, these Rayleigh and interface waves can interact with each other in the hanging wall to produce a" corner" shear wave with concentrated energy and thus the asymmetric seismic motion. Then, instead of considering only one single large-scale fault plane, more geometrically complex dip-slip faults that consist of damage zones with sets of smaller-scale parallel cracks are examined. The photoelastic study shows that depending on the dip angle, the rupture behavior may differ considerably. For a larger dip angle, secondary and further downward ruptures can be initiated, arrested and resume dynamic movement even without additional external load, seemingly due to the dynamic waves caused by the primary upward rupture.