The Seismic and Tsunami Threat to Ships, Personnel, and Defence Infrastructure on Canada’s West Coast

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Authors
  1. Mason, D.W.
  2. Zegers, A.
Corporate Authors
Defence R&D Canada - Centre for Operational Research and Analysis, Ottawa ON (CAN)
Abstract
The west coast of Canada is a high risk region for earthquakes and possible associated tsunamis. The commander of Maritime Forces Pacific/Joint Task Force (Pacific) requested an assessment of these threats, particularly the tsunami threat, to Royal Canadian Navy (RCN) vessels, personnel, and defence infrastructure on the west coast. This report brings together the extant geophysical science on the topic. The ‘offshore’ threat from tsunamis generated elsewhere around the Pacific Basin is characterized, as is the primary tsunami threat to coastal British Columbia – the Cascadia subduction zone. Probabilistic theory is developed to model subduction zone rupture events. The results confirm a likelihood of about one chance in ten of a major tsunami event happening on the west coast in the next 50 years. The severity of the tsunami in Esquimalt Harbour will be more modest if the 500-year event happens, with a predicted rise and fall of plus or minus three meters in water levels, but could be double that if the (unlikely but possible) 5,000-year event occurs. The tsunami amplitude will be doubled on exposed coastlines of Vancouver Island, and doubled again when focused in longer inlets (like Alberni Inlet). Warning times are estimated at 60 to 90 minutes in the Victoria area, but only 25 minutes on the outer coast. An assessment of the impact of changing water levels on docked RCN vessels and the effect of water inundation on defence infrastructure is provided.

Il y a un résumé en français ici.

Report Number
DRDC-CORA-TM-2013-185 — Technical Memorandum
Date of publication
01 Oct 2013
Number of Pages
96
DSTKIM No
CA039291
CANDIS No
800148
Format(s):
Electronic Document(PDF)

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