Dynamic source inversion based on stable formulation and on identification of the resolution level via a multiscale approach

Abstract

SUMMARY A dynamic rupture model is used to simulate source rupture processes based on the physical relationship between the stress and the strain field near a fault plane. When, however, a dynamic rupture model is used for inversion analysis, much computation time is required. We propose a new dynamic source inversion method, formulated by introducing a suitable set of dynamic parameters, ‘consolidated dynamic parameters’, which consists of rupture time, slip-weakening distance and dynamic stress drop, as estimating parameters. The rupture time is adopted for estimating parameters to derive stable formulation and to decrease CPU time. Compared with the conventional method, calculation time is much lessened. A multiscale approach to solve non-linear inversion problem is that the number of estimated values and the observation frequency ranges increase as the scale changes. Numerical results show the good reconstructing of target dynamic parameter distributions by the proposed inversion method.