Estimation of multivalued arrivals in 3D models using wavefront construction

We have developed a ray tracing based wavefront (WF) construction method that finds arrivals in general 3D models consisting of blocks with smooth velocity and density variation separated by interfaces where the velocity and density change discontinuously. The method is based on the ideas in Vinje et. al. (1992) and it mimics the true wave propagation in the lense that entire WFs are propagated time step by time step creating a moving surface travelling through the model. The WF may stretch, twist and fold in any way as it moves through the medium and the spatial sampling rate of the WF is kept above a pre-defined limit. The receivers are given value as the WFs pass them, one arrival for each sheet of WF that passes. Multi-arrival travel times, amplitudes, geometric spreading etc. are thus found in an efficient way in all areas of the model that are reachable by conventional rays.