CGRG Bibliography of Canadian Geomorphology
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Author : Clague, J.J.; Naesgaard, E.; and Mathewes, R.W.
Date : 1998
Title : Geological evidence for prehistoric earthquakes.
Publication : Geology and Natural Hazards of the Fraser River Delta, British Columbia. Edited by: J.J. Clague; D.C. Luternauer and D.C. Mosher. Geological Survey of Canada, Bulletin
Issue : 525:
Page(s) : 177-194.
Abstract
Geological and paleoecological evidence for two large, late Holocene earthquakes was found on the Fraser River delta and nearby Serpentine River floodplain. Both earthquakes triggered sudden land-level changes, and one caused extensive liquefaction. The younger quake occurred about 1700 years ago and is marked by submergence throughout the south-coastal region. Sand dykes, sand blows, and deformed strata at many sites on and near the Fraser delta may be products of the same earthquake; if so, earthquakes large and close enough to the delta to produce extensive liquefaction may be rare events. The land-level change and liquefaction may record a great (magnitude (M)=8+) plate-boundary earthquake on the Cascadia subduction zone, for which there is considerable evidence on the Pacific coasts of southern Washington and northern Oregon. However, they are more likely the result of a large crustal earthquake of about the same age within the North America plate. An older earthquake, which occurred about 3600 years ago, is marked by slight emergence of the Fraser delta and submergence on southern Vancouver Island. This pattern of deformation is consistent with a plate-boundary earthquake.
Bibliography of Canadian Geomorphology