Paleostress and Mechanisms of Slip on the San Gabriel Fault,San Andreas Fault System, California

浅威尔斯井主应力方向资料 表明圣安德烈亚斯断层上有低强度的剪切应力 加州。 这些数据与热流测量一致- 预测和预测，但与估计不一致 岩石的强度。 该项目将尝试测试hypo- 浅井数据是代表性的论点， 通过确定方位， 活动期间存在的主应力的位置 圣盖博断层现在已经被挖掘出来了 古应力方向 滑动的位置和机制将由岩石组构决定 断裂带的构造分析。 结果将 与实验室数据进行比较，并应用于 明显弱断层强度。

Data on principal stress orientation from shallow wells indicate a low magnitude shear stress on the San Andreas Fault, California. These data are consistent with heat-flow measure- ments and predictions, but are inconsistent with estimated strength of rocks. This project will attempt to test the hypo- thesis that the shallow well data are representative of the state of stress at mid-crustal depths by determining the orien- tation of the principal stresses that existed during activity on the San Gabriel fault, now deeply exhumed. Paleostress orien- tations and mechanisms of slip will be determined by petrofabric analysis of structures in the fault zone. Results will be compared to laboratory data and applied to the problem of the apparently weak fault strength.