A grid raytracing method for near-surface traveltime modeling

Accurate and efficient traveltime and raypath calculation is essential for successful application of a number of important near-surface imaging techniques. To this end, we have developed a grid raytracing method that incorporates two important developments in recent traveltime modeling research, namely, fast wavefront tracking and wavefront construction. By incorporating a fast wavefront tracking algorithm, the new method is more efficient than previous wavefront construction methods. Based on a local wavefront construction scheme, on the other hand, the grid raytracing method is more accurate in describing traveltimes and raypaths than the recently developed fast marching methods. Moreover, the new method is capable of modeling turning rays in arbitrary media and thus provides a suitable tool for near-surface traveltime modeling.