A method of shortest path raytracing with dynamic networks

作者：Zhang JZ^*; Chen SJ; Xu CW

来源：Acta Geophysica Sinica, 2004, 47(5): 899-904.

DOI：10.1002/cjg2.580

• shortest path algorithm
• dynamic network
• wavefront
• ray paths

The shortest path raytracing algorithm in networks is widely applied to calculate seismic ray paths and traveltimes, in which the beelines between network nodes are used to approximate the ray paths. When using a few nodes the ray usually follows a zig-zag path that is longer than the real raypath, and the calculated traveltime at a receiver is also larger than the real one. To solve this problem, we develop a shortest path raytracing method with dynamic networks based on the shortest path algorithm. In the process of expanding wavefront away from a source throughout the entire model, the wavefront times are sampled at all nodes on the cell edges. In each cell the traveltime at any point on an edge is expressed with linear interpolation between calculated traveltimes at adjacent nodes on the same cell edge, and then Fermat's Principle is used to determine the first arrival times at the nodes on the other edges of this cell. After the first arrival times at all nodes are calculated, trace raypath from a receiver to a source in the same way as the forward sampling for all pairs of receives and sources is performed. So the drawbacks of conventional shortest path raytracing methods are overcome, and the precision of calculated minimum traveltimes and the correspondent raypaths are improved greatly.

• 出版日期2004-9
• 单位厦门大学