Forward and Inverse Modeling of Rupture Dynamics in Three Dimensions

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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.