Integrating geodesy, seismology and dynamic rupture modeling: the 2010 Sierra El Mayor-Cucapah earthquake

研究人员计划对2010年4月4日下加利福尼亚州北部发生的不寻常的7.2兆瓦塞拉市长和库卡巴地震建立全面的模型。对这场地震进行了许多新的观察--S的行为，包括断裂断裂段之间的多重映射陡峭，目击者报告的局部破裂方向相反，以及地震的破裂长度(约100公里)比通常所见的同等规模的地震要长。我们将以两种方式模拟这一事件：首先，使用包含所有可用观测数据(例如InSAR、GPS、远震波形、强震波形、地质破裂数据)的运动学逆模型，以生成所涉及的断层段的真实地下几何形状，以及地震破裂期间这些断层上滑动是如何演变的图片。这将使用PI开发的基于贝叶斯最大似然的方法来实现。其次，他们将使用3D有限元代码生成正向动态地震破裂模型，该代码通过改变初始物理条件(例如，地震前的应力和摩擦条件)，试图重现运动学模型中和目击者看到的特征。最终的结果将是对地震如何以及为什么破裂的全面描述。将如此多样化的专业知识整合到单一的地震研究中是以前从未尝试过的。与单独应用任何一种技术相比，我们将对地震过程获得更多的洞察。此外，对地震中涉及的断层的详细描述将有助于我们评估其对南加州附近活动断层的潜在影响？除了通过会议和出版物传播我们的发现外，研究人员还打算通过开发博物馆的英语和西班牙语展品，在加州大学河滨分校和其他地方展示我们的发现，向公众传达我们的发现。

The researchers propose to generate comprehensive models of the unusual April 4th, 2010 Mw 7.2 Sierra El Mayor-­‐‑Cucapah earthquake in northern Baja California. A number ofnovel observations were made of this earthquake?s behavior, including multiplemapped stepovers between ruptured fault segments, eyewitness reports of locallyreversed rupture direction, plus the earthquake had a greater rupture length (~100 km) than is typically seen for an event of its size. We will model the event in two ways: first, with a kinematic inverse model that incorporates all available observational data (e.g. InSAR, GPS, teleseismic waveforms, strong motion waveforms, geologic rupture data) in order to generate both realistic subsurface geometries of the fault segments involved, and a picture of how the slip evolved on those faults during the earthquake rupture. This will be achieved using a Bayesian maximum likelihood-­‐‑based method developed by the PI. Second, they will produce forward dynamic earthquake rupture models using a 3D finite element code that seek to reproduce the features seen in the kinematic model and by eyewitnesses, by varying the initial physical conditions (e.g. pre-­‐‑earthquakestresses and frictional conditions.) The end result will be a full description of both how and why the earthquake ruptured.The incorporation of such a diverse range of expertise into asingle earthquake study has not been attempted before. We stand to gain more insights into the earthquake process than would be possible from applying any of the individual techniques in isolation. In addition, a detailed description of the faulting involved in the earthquake will help us to evaluate its potential effects on the nearby active faults in southern California ? the Elsinore and San Jacinto faults, and thus aid seismic hazard assessments in the region.In addition to disseminating findings through conferences and publications,the researchers aim to communicate our findings to the public by developing museum exhibits in both English and Spanish for display at UC Riverside and elsewhere.