Abstract

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.

You do not currently have access to this article.