Regularized Inversion of Coseismic Slip Distribution Based on Smoothness-Constrained Model
Advances in Geosciences
Estimating the spatial distribution of coseismic slip is an ill-posed inverse problem, and the solution is non-unique. In order to obtain stable solution for coseismic slip inversion, regularization method with smoothness-constrained was imposed. For the implementation of inverse algorithm, we construct a smoothness-constraint model with non-uniform slip on the fault plane, and propose a fast and stable method for choosing regularization parameter. In order to get reasonable coseismic slip
... coseismic slip distribution, non-negative least squares method is adopted. Inversion for a synthetic model with uniform coseismic slip distribution shows that the inverse algorithm is effective and stable, and non-negative least squares method can reconstruct reasonable results. We conduct inversions on the 2005 Nias earthquake with smoothness-constraint regularized method, and make a comparison of other results. The results for the 2005 Nias earthquake indicate the maximum slip is about 12.8 m, which agrees well spatially with the coseismic slip distribution of Konca. The released moment based on the estimated coseismic slip distribution is 9.91 × 10 12 Nm, which is equivalent to a moment magnitude (Mw) of 8.6 and almost identical to the value determined by USGS. The inversion results for synthetic coseismic slip distribution model and real earthquakes show that the smoothness-constrained regularized inversion method is effective, and can be reasonable to reconstruct coseismic slip distribution on the fault plane.