CGRG Bibliography of Canadian Geomorphology
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Author : Halchuk,S.; and Adams, J.
Date : 2001.
Title : Knowledge of in-slab earthquakes needed to improve seismic hazard estimates for southwestern British Columbia.
Publication : Annual Scientific Meeting of the Canadian Geophysical Union. May 14-17, 2001, University of Ottawa, Ottawa.
Issue :
Page(s) :
Abstract
In-slab earthquakes (earthquakes within the subducting Juan de Fuca plate) make the major contribution to seismic hazard for the Strait of Georgia region of British Columbia. These earthquakes dominate the hazard, despite their circa 50 km depth, because they occur at a rate up to 5-fold higher per unit area than the shallower crustal earthquakes, and their predicted shaking is stronger than from crustal events of the same size and distance. Different assumptions were adopted by the USGS (1997) and GSC 4th generation hazard maps (www.seismo.nrcan.gc.ca/seishaz4gen/hazintro.html) - for the recurrence slope (GSC beta=1.01; USGS beta=1.5) and the upper bound magnitude (GSC 7.3; USGS 7.0); w e find about 14-24% of the seismic hazard comes from earthquakes larger than those included in the USGS model. Therefore, key knowledge of in-slab earthquakes needed to improve seismic hazard estimates for southwestern British Columbia includes the constraints on the spatial distribution, rate and maximum size of the earthquakes, the ground motions to be expected, the nature of the earthquake sources, and the structure and properties of the lithosphere through which the waves propagate.
Bibliography of Canadian Geomorphology