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TitleField studies target 2012 Haida Gwaii Earthquake
AuthorJames, T; Rogers, G; Cassidy, J; Dragert, H; Hyndman, R; Leonard, L; Nykolaishen, L; Riedel, M; Schmidt, M; Wang, K
SourceEos, Transactions of the American Geophysical Union vol. 94, no. 22, 2013 p. 197-198,
Alt SeriesEarth Sciences Sector, Contribution Series 20120435
PublisherAmerican Geophysical Union
Mediapaper; digital; on-line
File formatpdf
ProvinceBritish Columbia; Western offshore region
NTS103B; 103C; 103F
AreaHaida Gwaii
Lat/Long WENS-132.5000 -131.5000 52.7500 52.0000
Subjectstectonics; geophysics; earthquakes; earthquake magnitudes; earthquake mechanisms; earthquake studies; tectonic environments; tectonic setting; tectonic interpretations; geological hazards
Illustrationslocation maps
ProgramTargeted Hazard Assessments in Western Canada, Public Safety Geoscience
AbstractAt 8:04 P.M. Pacifi c daylight time (PDT) on 27 October 2012 (03:04 universal time (UT), 28 October), Canada's second largest instrumentally recorded earthquake rocked Haida Gwaii (formerly Queen Charlotte Islands) and the mainland coast of British Columbia.
The M 7.7 event off the west coast of Moresby Island caused a tsunami with local runup of more than 7 meters and amplitudes up to 0.8 meter on tide gauges 4000 kilometers away in Hawaii. Shaking was felt as far away as the Yukon, Alberta, Washington, and Montana, up to 1500 kilometers away. Little damage was caused, as the immediate region is an uninhabited National Park Reserve. The closest point of the rupture zone, as defi ned by aftershocks (Figures 1a and 1c), was 50 kilometers from the nearest community, Queen Charlotte, where damage was confi ned to a few chimneys and slumped roads. The seismic waveforms, the pattern of aftershocks, and the coseismic motion determined from Global Positioning System (GPS) measurements indicate a low- angle thrust earthquake with motion signifi cantly different from the relative plate motion and almost perpendicular to the margin (Figures 1a and 1b). The epicenter is close to that of the
2001 M 6.1 thrust earthquake, which caused a small tsunami recorded on west coast tide gauges [Rabinovich et al., 2008]. New data
from instruments deployed shortly after the earthquake are helping scientists learn more about the earthquake and tsunami hazard of
the region.
Summary(Plain Language Summary, not published)
This article describes the Oct 27, 2012 M 7.7 Haida Gwaii earthquake, which was the second largest instrumentally recorded earthquake in Canada's history. It was an extremely large earthquake and it generated a tsunami, but because of the remoteness it caused little damage and no deaths. NRCan has mounted a substantial effort to deploy instruments, both on land and at sea, to better understand the characteristics of the earthquake, ensuing tsunami, and regional geological setting. This is expected to contribute to better understanding of earthquake and tsunami hazard along the Pacific coast of Canada and other locations worldwide where large thrust earthquakes occur in coastal settings.