The Haida cluster is named for the Haida Gwaii region off the west coast
of Canada. The cluster includes some earthquakes on the Queen Charlotte
Fault (QCF), which runs along the southwest edge of Haida Gwaii. Most of
the earthquakes on the QCF have azimuthal coverage that is too weak for
stable, robust locations. Prior to about 1990 there were too few seismic
stations in the area to support high quality relocation analysis.
Station coverage is quite good for earthquakes on Graham Island (the
more norhtern of two main islands comprising Haida Gwaii) and in the
sound between Haida Gwaii and the mainland. All events have depth
control, most from near-source and local-distance readings, and a few
events have teleseismic depth phase observations. The cluster retains
some events observed only to regional distances, but many events have
teleseismic observations.
