The Simulation Inversion And Application Of The Layered Spherical Model

Aiming at the inversion problem of the fault parameters in the layered spherical model,the defects of the genetic algorithm are pointed out by analyzing the the sensitivity and correlation of the inversion parameters.A new combinatorial inversion algorithm based on iterative least squares algorithm and genetic algorithm is proposed.The co-seismic deformation inversion mode due to seismic fault has set up considering the earth layering.The effectiveness of the combinatorial algorithm has been verified using the simulated data.In the inversion of genetic algorithm,fault depth and slip distance are often difficult to obtain good results.The mainly reason is the strong correlation between these parameters and the secondary reason is the low sensitivity of depth and slip.The combinatorial algorithm proposed in this paper has achieved ideal results on faults of various dip angles and has practicality.For the simultaneous retrieval of the fault parameters and Poisson's ratio,this paper first tries to use the genetic algorithm to do the work,and then analyzes the difficulty of using the co-seismic displacement field to calculating the Poisson's ratio because of the low sensitivity.The effect of Poisson's ratio variation of each layer on the co-seismic displacement field is quantitatively analyzed.In the range of 0.25-0.30,Poisson's ratio has very little effect on the inversion of fault parameters.Finally,the inversion method is applied to the inversion of the co-seismic fault in the L'Aquila earthquake in Italy.It is found that the proposed combination algorithm has a good effect in actual seismic cases.