标题： 东加州剪切带的地震源参数和断层运动学 显示英文标题

标题： Earthquake source parameters and fault kinematics in the Eastern California Shear Zone

摘要： 基于1992年6月28日Landers破裂事件在莫哈韦沙漠中南北走向的余震剖面的波形数据，我们构建了一个新的莫哈韦地区速度模型，该模型具有薄而慢的地壳。 使用这个模型，我们获得了剖面中每个余震的源参数，包括深度和持续时间，此外还包括1992年4月至1994年10月期间，任何显著（M>3.7）的Joshua Tree-Landers余震的源参数，这些余震有可用的相干TERRAscope数据。 总共，我们利用波形网格搜索算法，确定了与Joshua Tree和Landers序列相关的45个显著（M_w > 4）地震的源参数和应力降。 这些地震的应力降似乎相对于先前的地震活动、先前破裂的接近程度（即相对于Landers破裂）以及构造省，系统地变化。 一般来说，在Pinto Mountain断层以北的区域，位于与Landers破裂相关的断层之外的余震的应力降高于位于断层上的余震，但新识别的Kickapoo（Landers）断层上的余震除外。 在Pinto Mountain断层以南，应力降适中，该地区有地震群的历史，但没有单一的贯穿断层。 与东部横断山脉的余震相反，并与1992年加州Big Bear事件相关，Landers事件中应力降与深度之间没有明显的关系。 相反，高应力降的余震似乎与新生断层或主震破裂期间相对滑动较小的断层有关。 显示英文摘要

摘要： Based on waveform data from a profile of aftershocks following the north-south trace of the June 28, 1992 Landers rupture across the Mojave desert, we construct a new velocity model for the Mojave region which features a thin, slow crust. Using this model, we obtain source parameters, including depth and duration, for each of the aftershocks in the profile, and in addition, any significant (M>3.7) Joshua Tree--Landers aftershock between April, 1992 and October, 1994 for which coherent TERRAscope data were available. In all, we determine source parameters and stress-drops for 45 significant (M_w > 4) earthquakes associated with the Joshua Tree and Landers sequences, using a waveform grid-search algorithm. Stress drops for these earthquakes appear to vary systematically with location, with respect to previous seismic activity, proximity to previous rupture (i.e., with respect to the Landers rupture), and with tectonic province. In general, for areas north of the Pinto Mountain fault, stress-drops of aftershocks located off the faults involved with the Landers rupture are higher than those located on the fault, with the exception of aftershocks on the newly recognized Kickapoo (Landers) fault. Stress drops are moderate south of the Pinto Mountain fault, where there is a history of seismic swarms but no single through-going fault. In contrast to aftershocks in the eastern Transverse ranges, and related to the 1992 Big Bear, California, sequence, Landers events show no clear relationship between stress-drop and depth. Instead, higher stress-drop aftershocks appear to correlate with activity on nascent faults, or those which experienced relatively small slip during mainshock rupture.