High-accuracy wavefront tracing traveltime calculation

摘要: Conventional ray-tracing algorithms for first-arrival calculation suffer from drawbacks such as (1) no guarantee of finding the globally minimum traveltime path when multiple paths exist, (2) shadow zones, and (3) trouble containing refraction and/or diffraction energy. Algorithms that trace wavefronts circumvent these problems. The new wavefront-tracing algorithm presented here is based on an earth model consisting uniform-velocity triangular cells with nodes placed at vertices along cell edges. Nodes are places where traces first arrival (propagation directions times) stored. works by propagating (sampled nodes) away source throughout entire model. Wavefronts propagated locally diffraction, direct arrival, or critically refracted energy implicitly describe time paths. Once wavefront sampled model, traveltimes raypaths sour...