A revision of the plate boundary configuration offshore southern Haida Gwaii, which is the locus of the 2012 M w 7.8 thrust earthquake, is based on a re‐evaluation of regional geophysical data and leads to recognition of fault segments critical for seismic‐hazard analysis. Off western Canada, the strike‐slip Queen Charlotte fault (QCF) and Revere–Dellwood fault (RDF) constitute the transpressive plate boundary between the Pacific and North American plates. The southernmost 80 km of the QCF strikes at the highest angle (∼20°) to the relative plate motion, yet geomorphology adjacent to the fault is the most subdued. Synthesizing geomorphology, seismicity, sidescan sonar, gravity, and seismic reflection profiles indicates that the plate boundary is evolving to a less transpressive configuration than previously interpreted. The RDF is 100 km longer than previously mapped; it has propagated northward and overlaps the QCF by 120 km. Propagation is defined by strike‐slip earthquakes 3.9 M w M w 7.8 and the 1949 M 8.1 earthquakes.
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K. M. M. Rohr (2015) studied this question.