Seismic systems and processes for making and using same. In some examples, the seismic system can include an acoustic tool configured for placement in a wellbore penetrating a subterranean formation. The acoustic tool can include an acoustic transmitter unit for producing acoustic energy waveforms in the subterranean formation such that the interaction of the acoustic energy waveforms with structures in the formation can be an event that generates event signals. A receiver unit can include acoustic receivers distributed azimuthally around a central axis of the acoustic tool for sensing the event signals. The acoustic tool can determine event signal amplitudes of the event signals at each of the acoustic receivers, can determine which of the acoustic receivers has a maximum amplitude of the event signal amplitudes, and can interpolate between the maximum amplitude acoustic receiver and one or more adjacent acoustic receivers to find an azimuthal direction of the event.