A method can include receiving seismic data responsive to stimulation of an anisotropic formation via a well disposed in the formation; receiving crosswell calibrated velocity model information that spans a depth range of the anisotropic formation; locating a microseismic event generated by the stimulation based at least in part on a portion of the received seismic data and based at least in part on the crosswell calibrated velocity model information; and rendering the located microseismic event to a display with respect to one or more dimensions of the anisotropic formation.