A modified simulated annealing for first-arrival time inversion

Travel times inversion generally is a nonlinear problem of optimization. In this paper, we propose a modified simulated annealing(MSA) to invert first arrival times for velocities. MSA draws new models from a Cauchy-like distribution, which is a function of temperature, and uniform design method. The advantage of using MSA is that it can reduce the computational cost of SA greatly. In addition, a fast finite difference solution of the eikonal equation is used to compute first arrival times through the velocity models which computes objective function efficiently. Synthetic examples indicate that our scheme is much less computational effort than conventional simulated annealing.