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On the lookout for the next tsunami

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Canada’s long coastlines make it vulnerable to natural disasters. Tsunamis, for example, can be created by earthquakes, landslides underwater or on land, volcanic eruptions, or meteorite impacts.

If a tsunami occurs in the Pacific Ocean, the first warning will come from an internationally co-ordinated network of seismographs. The Geological Survey of Canada maintains over 30 seismic stations within 300 kilometres of British Columbia’s coast. These stations feed real-time data to authorities in areas vulnerable to tsunamis so they can initiate contingency plans.

Canada has not seen, in recorded history, an event on the scale of the tsunami that swept from Indonesia across the Indian Ocean on December 26, 2004. However, on November 18, 1929, a magnitude 7.2 earthquake occurred at the southern edge of the Grand Banks, 280 kilometres south of Newfoundland. The earthquake triggered the largest underwater landslide in recorded Canadian history—a displacement of 200 cubic kilometres of sediment that travelled along the ocean floor.

The resulting tsunami was the worst on record for Canada: waves with heights of between 3 and 8 metres and a run-up of up to 13 metres struck communities on the BurinPeninsula—at peak tide. Twenty-eight people perished; property damage was extensive.

Following the Indonesian crisis, Canada implemented a tsunami warning system on the Atlantic coast. An extensive system was already in place on the Pacific coast—over 70% of tsunamis occur in the Pacific Ocean. Now, the AtlanticStormPredictionCenter’s capability to issue surge and other weather-related warnings has been upgraded to include tsunamis, at a cost of about $250,000.