Ray equation migration of wide‐angle reflections from southern Alaska

A Kirchhoff‐style prestack depth migration algorithm is implemented for wide‐angle reflections in two‐dimensional variable‐velocity (acoustic) media. Extrapolation of both source and recorder wavefields is performed by ray tracing. The imaging condition at each point in the image space is the total source to recorder travel time. Since the migration algorithm is based on ray tracing, migration can be performed for any medium through which rays can be traced. There is no inherent limitation on the size of the region to be imaged; regions up to 3.6 × 10 3 km 2 are utilized in this study. The algorithm is illustrated by migration of two synthetic and three real data sets from the U.S. Geological Survey's Trans‐Alaska Crustal Transect program. Images are produced of inferred subduction assemblages in southern Alaska. Emphasis in this paper is on obtaining reflector positions and shapes rather than detailed structural interpretations.