Concerning the analysis of data from seismic reflection survey, time migration and DMO treatment are discussed. As a tool for dealing with irregular changes in elevation, a technique is developed that can define the local reference level working effectively in the Kirchhoff-type treatment. In this technique, for each migration or dipmovement trace outputted, processing is repeatedly performed for imaging and local reference level. In dealing with the curvature of a traverse line, a 3-dimensional DMO treatment with cross-dip correction is performed, for the development of a method for simultaneously applying projection and accumulation to stacked traverse lines. A migration projection plane is set separately from the CMP traverse line, and this enables a quasi-3-dimensional treatment approximately corresponding to the curvature of the traverse line. A technique to respond to irregular shock points is discussed, in which input traces corrected by NMO having uniform amplitude distribution are presumed, DMO treatment is conducted for each irregular shock point, and the results are used as a normalization factor usable in the process of real DMO stacking. 6 refs., 2 figs.