The hypocentral resolution of microearthquake surveys carried out at sea

Summary. The ability to locate the hypocentres of earthquakes occurring along ridge crests and fracture zones accurately is a prerequisite to solving several problems associated with seafloor tectonics and oceanic crustal formation. Such resolution has rarely been achieved in the past, often because the seismic networks deployed were inadequate for the task. We demonstrate that sea surface receivers are not useful in such studies, and that the minimum acceptable size for a seafloor network is five receivers, of which at least one must be capable of detecting shear waves unambiguously.