One embodiment relates to a technological process for identifying a potential subsurface structure below a body of water. Three-dimensional seismic sensor data that includes at least two measured components is obtained. Up-going and down-going wavefields comprising multiples wavefields are constructed from the three-dimensional seismic sensor data by applying wavefield separation. The up-going and down-going wavefields are extrapolated to a reflector surface below a water bottom. An imaging condition is applied at the reflector surface to generate images that include information from the multiples wavefields. Angle gathers are constructed, where each angle gather is constructed by gathering the images generated using the multiples wavefields for a range of illumination angles. Other embodiments, aspects and features are also disclosed.