1. A method of providing an improved seismic dataset comprising: (a) providing an initial basin model constructed using an initially-available dataset comprising at least some initially available seismic velocity data, and using a selected subset of the initially available seismic velocity data as calibration inputs to the initial basin model; (b) constructing a velocity dataset from the initial basin model; and (c) reprocessing the initially available seismic data using the velocity dataset from the initial basin model as a guide, to form the improved seismic, dataset.