Traveltimes computation using linear interpolation and narrow band technique under complex topographical conditions
复杂地表条件下基于线性插值和窄带技术的地震波走时计算

For realizing the seismic traveltime computation under complex topographical conditions, we present a new method based on linear interpolation and narrow band technique. Here, the linear interpolation technique is used for carrying out the local traveltime computation, and the narrow band technique is used for capturing and propagating the wavefront. For fitting the complex topography, we use a hybrid grid, consisting of a triangular grid and a rectangular one, for dividing the velocity model into grid. For obtaining a formula for the local traveltime computation, we invoke the Fermat principle and a condition for limiting the position of the incident point. Programming practice and numerical tests show that the new method not only can treat the strong topographical change with effectiveness and flexibility, but also have satisfactory stability and adaptability to the complex velocity model. The results given by the new method consist with the laws on wave propagation.