3-D structural reconstruction of Moho in the Tangshan earthquake area by using inversion of curved interface

A method for inverting 3-D curved interface and layer velocity by using travel time of reflected waves is studied. Each interface is described with sectional, incomplete cubic polynomial. A fast 3-D ray tracing method is used in forward problem, and a least squares method with variable damping is adopted in the inverse problem. Result from numerical modelling shows that the solution can converge fast on the true model. Observational data from the Tangshan earthquake area are processed, 3-D Moho discontinuity in the area is rebuilt, and finally, the relationship between the regional structure and seismicity is revealed.