Forward and Inverse Modeling of Rupture Dynamics in Three Dimensions

题目：破裂动力学的三维正逆建模[j]: Kim Olsen，加州大学圣巴巴拉分校地壳研究所。该研究是一种综合方法，可以显著提高我们在地震破裂动力学领域的知识。这项工作由三部分组成。第一部分是在横向和纵向非均质三维介质和精确边界条件下，建立具有辐射的弯曲或多段断层几何上动态破裂传播的灵活高效建模方法。这种方法将允许在任意形状的断层系统上对反复破裂的统计进行完全大规模的动态建模。在这里，我们将结合几种数值方法最灵活和最有效的特点。第二部分是对定义动态破裂开始、传播和停止的关键参数和条件的持续努力。这包括对非均匀应力场中动态破裂速度变化的分析，特别是推导出与观测结果一致的产生破裂传播的参数的表达式并对其进行数值估计。第三部分将研究对大地震的摩擦、应力或破裂能进行反演的可行性，这些参数包含有关破裂历史的关键信息。我们将描述反演的局限性和准确性，并尝试将该方法应用于选定的记录良好的大地震。这三个部分的研究都是为了实现这个项目的最终目标，即更好地理解地震为什么会发生、传播和停止。这样的了解可能导致未来地震的成功预测，从而减少生命和财产的损失。

Abstract for proposal EAR0003275 (PH #23x)Title: Forward and Inverse Modeling of Rupture Dynamics in Three DimensionsPI: Kim Olsen, Institute for Crustal Studies, University of California at Santa BarbaraThe proposed research is an integrated approach to significantly advance our knowledge in the field of earthquake rupture dynamics. The work consists of three parts. The first part is the development of a method for flexible and efficient modeling of dynamic rupture propagation on curved or multi-segmented fault geometries with radiation in a laterally and vertically heterogeneous three-dimensional medium and accurate boundary conditions. This method will allow fully large-scale dynamic modeling of the statistics of recurrent ruptures on systems of arbitrarily-shaped faults. Here, we will combine the most flexible and efficient features of several numerical methods. The second part is a continuation of ongoing efforts on defining the critical parameters and conditions describing when dynamic rupture start, propagate, and stop. This involves an analysis of the variation of dynamic rupture velocity in a heterogeneous stress field and in particular, deriving expressions for and numerically estimating the parameters generating rupture propagation in agreement with observations. The third part will examine the feasibility of inverting for the friction, stress, or fracture energy, parameters containing key information about the rupture history, for large earthquakes. We will describe the limitations and accuracy of the inversion, and attempt to apply the method to selected large, well-recorded earthquakes. The three parts of the proposed research all lead towards the ultimate goal of the project, namely to better our understanding of why do earthquakes start, propagate and arrest. Such understanding may lead to successful prediction of earthquakes in the future, thereby mitigating the loss of life and property.