A shortest-path-aided fast sweeping method to improve the accuracy of travel time calculation

The high accuracy and efficiency of travel time calculation are critical in seismology. The fast sweeping method (FSM) is an efficient approach to solve the Eikonal equation. However, the FSM is accurate only along the axis directions. In two-dimensional or higher dimensional cases, the accuracy is severely decreased in the diagonal directions due to the numerical errors in these ray directions.

To improve the accuracy of travel time calculation in two-dimensional or higher dimensional space, a shortest-path-aided fast sweeping method (SPAFSM) is proposed. The shortest-path-aided solution is embedded into the sweeping process of the standard FSM to improve the travel time accuracy in the diagonal directions. SPAFSM is very easy to implement without extra additional computational cost and memory consumption. And it is easy to extend from two-dimensional to a higher dimensional case.