Accurate Three Dimensional Calculations for Advancing Slip Zones in the Earth's Crust

将一种精确有效的弹性固体裂纹三维分析方法应用于地壳准静态推进滑移带的研究。进行计算是为了确定由于剪切断层进入或围绕锁定的或更具抵抗力的浅地壳部分而产生的应力和表面变形。特别值得注意的是，推进锋面上的不均匀是不稳定的，从某种意义上说，它们引起滑动的快速自发传播，以及可能区分小震和大震的条件。这些计算还可能将地表形变的测量与地震活动性的增加联系起来，地震活动性的增加可能是由伴随滑移带推进的应力的上升所触发的。考虑的其他影响包括自由面上发生崩塌的可能性，以及由于自由面的存在而引起的法向应力和剪应力的耦合。最初的研究将是走滑几何学，可能应用于南加州的帕克菲尔德地区，但该方法的多功能性也允许研究逆冲断层。

An accurate and efficient method for the three-dimensional analysis of cracks in elastic solids is applied to the study of quasi-statically advancing slip zones in the earth's crust. Calculations are done to determine stresses and surface deformations due to the advance of shear faults into and around locked, or more resistant, portions of the shallow crust. Of particular interest are conditions for which non-uniformities in the advancing front are unstable, in the sense that they give rise to rapid spontaneous propagation of slip, and conditions that may distinguish small from large earthquakes. These calculations also make it possible to relate measurements of surface deformation to increases in seismicity that may be triggered by the elevation of stresses that accompanies slip zone advance. Other effects considered are the possibility of breakout at the free surface and the coupling of normal and shear stress due to the presence of the free surface. Initial studies will be for strike-slip geometries for possible application to the Parkfield region of southern California, but the versatility of the method allows study of thrust-faults, as well.