1. In a basin environment encompassing sedimentary rocks disposed insitu in subsurface sequences, from which well log data, including sonic data, have been obtained downhole, and from which seismic time sections and seismic velocity data derived from spectra, at discrete locations, have been obtained, a computerized method of evaluating velocity distributions and interpreting spatial distributions of said subsurface sequences, and of interpreting depositional and post-depositional and resolution errors thereof, for exploring and prospecting for subsurface hydrocarbon reservoir, seal, trap or source, said method comprising the steps of: converting said seismic velocity data to reveal presence of seismic lithological sequences; determining spatial velocity behavior of said seismic lithological sequences at available points of velocity control; plotting interval velocity versus depth for said velocity control, for each sequence of said seismic lithological sequence, to determine compaction characteristics; ascertaining apparent lithology related to said sedimentary rocks at the depth and velocity established from said determining spatial velocity behavior and plotting interval velocity versus depth steps; constraining said sequence velocity distribution by applying adjustable filters which identify and reject evidence of velocity behavior deemed to be impossible on the basis of estimated depth, velocity, compaction and lithology, for prognosticating locations in said basin environment for exploring and prospecting for said subsurface hydrocarbon reservoir, seal, trap or source; and storing said rejected velocity evidence and its associated location parameters in a database for use in subsequent analysis of said subsurface sequences.