Tomography of a Minimum Travel Time Ray Tracing on a Triangular Net

In view of problems existed in tomography on rectangular net subdividing to a model,we proposed a triangular net minimum travel time ray tracing tomography method for complex structure.A triangle grid was subdivided based on the Delaunay triangular subdividing criterion and the relationships among the points,lines,and surfaces of the model.The first travel times was calculated with triangular net plane wave propagation method,followed by tracing the ray paths of any receiving point to the excitation point.The ray paths include the informations of the coordinates from receiving points to source points and all triangle cells,and the matrix equation is formed.The matrix equation is conducted by applying SIRT algorithm and the velocity distribution is obtained.The simulation results show that the use of triangular net ray tomography method achieved higher resolution version,and more precisely reflected the actual morphological characteristics.The problems of inflexibility of subdividing elastic wave tomography for complex structure models,and poor definition of velocity interfaces is effectively resolved.