1. A computer-implemented method of creating a high-resolution velocity model of a geological medium from seismic data, comprising: generating a long-wavelength anisotropic velocity model by performing a tomographic inversion of one or more seismic data gathers using moveout data derived from the one or more seismic data gathers; accessing an attenuation model that includes frequency-dependent attenuation factors for each of a plurality of locations in the geological medium; combining the long-wavelength velocity model with the attenuation model to produce a long-wavelength velocity and attenuation model; performing prestack depth migration on the one or more seismic data gathers from a time domain to a depth domain using the long-wavelength velocity and attenuation model to produce one or more seismic image gathers; applying a dip-consistent filter to the one or more seismic image gathers to produce one or more filtered seismic image gathers; transforming the one or more filtered seismic image gathers from the depth domain to the time domain; generating a full-band impedance model for the geological medium by performing an impedance inversion of the one or more filtered seismic image gathers in the time domain using the long-wavelength velocity and attenuation model; applying a spatial-coordinate-independent calibration to the full-band impedance model using one or more frequency-spectral calibration factors determined from one or more of well-log derived velocities, well-log derived impedances, and high-contrast horizons to produce a frequency calibrated full-band impedance model; and detecting fluid pressure anomalies in the geological medium using the frequency calibrated full-band impedance model.