A slowness vector (p) is defined. Its component (px) follows a direction parallel to the seismic data acquisition line, defining the gradient of the cylindrical wave. For a seismic sensor located at the abscissa (xr) on the acquisition line, the abscissa (xi) of the point source on the line of acquisition is sought, such that a radius from the sensor reflected at a point event, emerges at the point source with a slowness vector (p) with a component following the eastern acquisition line (-px). The propagation time (te(xR)) is determined, adding to the duration of propagation along the radius, a time equal to the product of the gradient of the cylindrical wave through the abscissa of the point source. The previous two foregoing stages are repeated for all sensor positions for which a propagation analysis result is required. All stages are repeated for all values take by the px parameter, for which an event has been identified in the corresponding propagation data. Preferred features: A further procedure based on the foregoing principles is described. The method is used in a tomatographic technique, in which cylindrical wave reflection is employed and the velocity distribution is calculated in the seismic medium. Propagation times resulting from features are converted to depths. Transformations are applied to the results from the seismic arrays, using single- and double extrapolation techniques in azimuth-orthogonal directions.
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