CGRG Bibliography of Canadian Geomorphology
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Author : Bornhold, B.; Rabinovich, A.B.; Skvortsov, A.; Fine, I.V.; Kulikov, E.A.; and Thomson, R.E.
Date : 2004.
Title : Landslide-generated tsunamis and their risk in coastal areas.
Publication : Geo-Engineering for the Society and its Environment. 57th Canadian Geotechnical Conference and the 5th joint CGS-IAH Conference. Hilton Quebec Hotel, Old Quebec. October 24-27, 2004.
Issue :
Page(s) :
Abstract
Traditionally tsunamis have been viewed as being mainly a direct consequence of fault movements in oceanic areas and associated with large earthquakes. In recent years researchers have come to recognize that underwater landslides, whether triggered by large seismic events or not, can give rise to devastating tsunamis impacting coastal areas. The largest tsunami of the twentieth century, for example, (Papua New Guinea, 1998) was a consequence of a very large submarine slope failure triggered by a moderate earthquake. In this paper we review some of our modeling approaches and results for several historical tsunamis which have had serious impacts on coastal areas of North America. The devastating tsunamis we review were created by subaqueous failures on continental slopes and coastal inlets, by combined subaerial/subaqueous failures in fjords and by subaerial failures entering coastal waters. The nature of the failure governs the magnitude and character of the tsunami generated; in this study, based on the geological information available, we have modeled the various failures/tsunamis as generated by block slides, by debris flows and by flow slides. In November 1994, at a very low tide a fjord-wall flow slide at Skagway, Alaska created a local tsunami estimated to have a magnitude of more than 10 m. The event caused the death of one worker and significant damage to various harbour facilities. Modelling of the event was successful in accounting for the wave and its characteristics in relation to the failure scenario. In April 1975, a largely subaqueous debris flow near Kitimat, British Columbia created a local tsunami approximately 8 m high which caused considerable damage to vessels and port facilities; this failure also took place on an extreme low tide. In November, 1929, a moderate earthquake on the continental slope off Newfoundland resulted indirectly in Canada’s most devastating known tsunami, causing 27 deaths along the southern coast of Newfoundland; the earthquake triggered a massive slope failure which gave rise to the tsunami. A potentially even more significant tsunami may have occurred in central Knight Inlet, British Columbia at an unknown time in the past; native stories, corroborated by air photo and seabed evidence, report the side of a mountain falling into the inlet and creating a large wave that swept over a village at the mouth of the Kwalate River, forcing its abandonment. These events, their causes and our approaches to modeling them are discussed.
Bibliography of Canadian Geomorphology