 Shallow earthquakes consistent with strike-slip faulting occur on the western side of the zone, but their large distribution indicates that multiple faults exist.Generally these faults run along the walls of the bathymetric basins, but near the Juan de Fuca ridge they become distorted, and rotate towards the ridge axis instead.On January 9, 1994, a large series or swarm of earthquakes occurred in the East Blanco Depression.