On Tuesday, a massive 8.8 magnitude earthquake struck the region near Russia’s Kamchatka Peninsula, prompting worldwide tsunami alerts. People from Hawaii to Japan, the B.C. coast to Chile and Australia were cautioned about potential coastal flooding.
The catastrophic 2004 Boxing Day tsunami, triggered by a 9.1 magnitude earthquake off Sumatra, Indonesia, claimed over 280,000 lives and displaced more than a million individuals in south Asia and east Africa. Another notable event was the 2011 Tohoku earthquake and tsunami in Japan, which led to the shutdown of the Fukushima nuclear power plant and caused over 15,000 fatalities.
Tsunamis, a series of waves created by ocean water displacement, can vary in height from centimeters to tens of meters, causing devastation by engulfing homes, structures, and people. These waves can traverse entire ocean basins, as evidenced by the recent Kamchatka earthquake reaching from the north Pacific to the south Pacific and even as far as New Zealand.
The majority of tsunamis, about 80%, stem from earthquakes, although they can also result from underwater or above-water landslides. On rare occasions, atmospheric changes can induce meteotsunamis like the one suspected to have occurred on Lake Superior in June near Thunder Bay, Ontario.
Underwater landslides triggered by moderate earthquakes can extend for hundreds of kilometers, displacing significant amounts of water and leading to tsunamis. Megathrust earthquakes in the Cascadia Subduction Zone off the B.C. coast pose a significant risk, potentially causing a tsunami with a magnitude of nine or more.
Tsunamis, especially large ones like the Sumatra and Tohoku events, are infrequent occurrences, happening once every couple of hundred to a thousand years in a particular location. The Global Historical Tsunami Database notes that dangerous tsunamis happen around twice a year, with larger, more damaging tsunamis striking over 1,000 kilometers away occurring about twice per decade.
Canada faces tsunami risks, particularly along the B.C. coast due to its proximity to the Cascadia Subduction Zone, where megathrust earthquakes can trigger devastating tsunamis. Natural Resources Canada estimates that such earthquakes occur every 200 to 800 years, with minimal time for warning between the earthquake and ensuing tsunami waves.
While less active than the Pacific Ocean’s “Ring of Fire,” the North Atlantic Ocean holds potential tsunami threats. Past events like the 1929 earthquake off Newfoundland and Nova Scotia demonstrate the region’s vulnerability to tsunamis triggered by underwater landslides.
Prevention of tsunamis is impossible, emphasizing the importance of robust warning systems and evacuation plans. Early warnings and evacuation training are critical for saving lives in the event of a tsunami, as seen in the recent earthquake and tsunami response.
