Crooked line, rough topography: advancing towards the correct seismic image

Seismic exploration in mountainous areas imposes serious compromises on bot h acquisition and processing. Access restrictions usually result in profile s that are not straight and are not recorded along the true dip direction ( if there is a true dip direction!). Processing constraints often result in very poor approximate corrections for elevations and for deviations from a straight Line. Most fundamentally, 2D acquisition and processing assumes th at the earth is 2D; this assumption is often seriously violated in mountain ous areas. While we cannot efficiently correct 2D seismic data for the effe cts of a fully 3D subsurface, we can improve the data quality in thrust are as where the assumption of 2D subsurface variation is reasonable. We do thi s in a series of small steps, which improves the accuracy of several approx imations made in processing 2D land data.