Earthquake Hazard in Canada

Most Canadians live in low seismic zones, but Vancouver, Victoria, Montreal, and Quebec City sit on active crustal faults or near subduction zones. Peak ground acceleration (PGA) quantifies expected shaking intensity for building code design; higher values require stronger structural detailing.

Standard home insurance in Canada does not cover earthquake damage by default. Homeowners in high-hazard regions typically add a separate earthquake endorsement priced specifically for their location, and pricing reflects the concentrated geography of Canadian seismic hazard described above; retrofit programs exist in BC and Quebec for unreinforced masonry and soft-story buildings.

How the national seismic hazard model is built

Unlike flood or wildfire risk, seismic hazard changes very little from one year to the next for a given site. What does change periodically is the underlying hazard model itself, as the Geological Survey of Canada incorporates new earthquake records, refined fault mapping, and improved ground-motion science into successive generations of the national hazard maps, each tied to a specific edition of the National Building Code. The Geological Survey of Canada, part of NRCan, is responsible for the probabilistic seismic hazard model that underlies Part 4 of the National Building Code of Canada seismic design values. The model draws on the historical earthquake catalogue, known fault systems, and regional tectonic setting to estimate ground motion values, expressed as peak ground acceleration and spectral acceleration, at a defined probability of exceedance, most commonly 2% in 50 years, the standard basis for building code design. The model is revised periodically as new geological and seismic data become available; it does not track individual earthquakes in real time so much as the long-run statistical hazard for a given site.

Two zones, two different mechanisms

Western Canada's hazard is driven primarily by the Cascadia subduction zone, where the Juan de Fuca plate is being forced beneath the North American plate off the coast of Vancouver Island, a setting capable of producing very large magnitude events over long recurrence intervals, alongside more frequent shallower crustal earthquakes within the plate itself. Canada's largest recorded historic onshore earthquake, a magnitude 7.3 event centred on Vancouver Island's Forbidden Plateau in June 1946, was one of these crustal events rather than a subduction-zone rupture, and it knocked down roughly three quarters of the chimneys in the nearest communities. The St. Lawrence Valley zone in Quebec and eastern Ontario has a different, less understood mechanism tied to ancient rifting structures in the earth's crust; the Charlevoix region has produced several of the largest earthquakes in eastern North America's recorded history, including a magnitude 6.2 event in 1925 felt more than 1,000 kilometres from its epicentre.

Earthquake early warning

NRCan's Earthquake Early Warning system became operational in British Columbia in 2024, with the eastern Ontario and southern Quebec portion following in autumn 2025, extending coverage to more than 10 million people in Canada's two highest-hazard regions. The system uses a network of ground sensors to detect an earthquake above roughly magnitude 5 near its source and push an automated alert through Alert Ready before strong shaking reaches more distant locations, providing anywhere from a few seconds to tens of seconds of warning depending on distance from the epicentre. That window is used both for public protective action (drop, cover, and hold on) and for automated responses in infrastructure, such as slowing trains and restricting bridge and tunnel access, rather than for evacuation, since there is not enough lead time to leave a building safely.

Retrofit programs and older building stock

British Columbia and Quebec both run structural retrofit initiatives aimed at the building types seismic engineers consider highest risk: unreinforced masonry buildings constructed before modern reinforcement standards became common, and soft-story wood-frame buildings with a weak ground floor, often older apartment blocks with parking or retail at street level. The BC School Seismic Mitigation Program has prioritized retrofitting or replacing schools built before the province's seismic design provisions were substantially strengthened following the 1946 Vancouver Island earthquake and later code updates, since school buildings are treated as higher-consequence structures given occupant numbers and their use as emergency shelters after a major event. Municipal seismic upgrade bylaws in Vancouver and Victoria target unreinforced masonry buildings specifically, requiring assessment and, in some cases, mandatory retrofit within a set timeline.

What homeowners in higher-hazard zones can do

• Ask your insurer directly whether earthquake coverage is included or must be added as an endorsement, and compare the deductible, which is often a percentage of the insured value rather than a flat dollar amount.
• Secure water heaters, tall furniture, and heavy wall-mounted items, since falling objects cause a large share of earthquake injuries.
• Know how to shut off gas, water, and electricity at the main, and keep the tools to do so accessible.
• Homes built before the mid-1970s in BC or Quebec, before modern seismic code provisions, may benefit from a structural assessment, particularly unreinforced masonry chimneys and foundations.

For flood, wildfire, and earthquake risk together, see the OpenStats natural hazards guide.