1. A method of developing a velocity model for processing a seismic dataset, comprising: at a computer system having a processor and memory: deriving a first velocity model from the seismic dataset; building a basin model based on the first velocity model and interpretation of the seismic dataset; validating the basin model using calibration data; deriving a second velocity model from the validated basin model; and updating the first velocity model based, at least in part, on the second velocity model.