An earthquake occurred at 10 h 16 m 39 s GMT on 5 July 1972 in close proximity to the west coast of Vancouver Island, near 49.5 °N and 127.2 °W. Its magnitude (mb) was 5.7 and the hypocenter was near the middle of the crust. A well defined P nodal solution has a pressure axis with a north-south orientation and a tension axis with an east-west orientation. The preferred nodal plane suggests right lateral strike-slip faulting on a near vertical fault, striking in a north-northwest direction. The other nodal plane suggests that left lateral strike-slip faulting on a near vertical fault striking in an east-northeast direction is also a plausible solution. A field study with portable seismographs revealed that very few aftershocks were associated with this earthquake. The largest aftershock had a magnitude (ML) of 3.4. The distribution of intensity of the mainshock observed on Vancouver Island differs from that predicted by the intensity versus distance relation presently used for western Canada.

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