The Vulnerability of Canada to Volcanic Hazards
Source: Natural Hazards, Volume 28, Numbers 2-3, March 2003 , pp. 563-589(27)
Western Canada lies in a zone of active tectonics and volcanism, but the dispersed population has witnessed few eruptions due to the remoteness of the volcanoes and their low level of activity. This has created a false perception that Canada's volcanoes are extinct.
There are more than 200 potentially-active volcanoes in Canada, 49 of which have erupted in the past 10,000 years. They occur in five belts, with origins related to tectonic environment. The minimum annual probability of a Canadian volcanic eruption is approximately 1/200; for an effusive (lava) eruption the probability is about 1/220, and for a significant explosive eruption it is about 1/3333. In-progress studies show that there have been earthquakes associated with at least 9 of the youngest Canadian volcanoes since 1975. A scenario of an eruption of Mt. Cayley (50.1°N, 123.3°W) shows how western Canada is vulnerable to an eruption. The scenario is based on past activity in the Garibaldi volcanic belt and involves both explosive and effusive activity. The scenario impact is largely a result of the concentration of vulnerable infrastructure in valleys.
Canadian volcanoes are monitored only by a regional seismic network, that is capable of detecting a M > 2 event in all potentially-active areas. This level of monitoring is probably sufficient to alert scientists at or near eruption onset, but probably insufficient to allow a timely forecast of activity. Similarly the level of geological knowledge about the volcanoes is insufficient to create hazard maps. This will improve slightly in 2002 when additional monitoring is implemented in the Garibaldi volcanic belt. The eruption probabilities, possible impacts, monitoring limitations and knowledge gaps suggest that there is a need to increment the volcanic risk mitigation efforts.
Document Type: Research Article
Affiliations: 1: Geological Survey of Canada, Pacific Division, 101-605 Robson Street, Vancouver, British Columbia, V6B 5J3, Canada 2: Geological Survey of Canada, Pacific Division, Pacific Geoscience Centre, Sidney, British Columbia, Canada
Publication date: 2003-03-01