What would happen if a large earthquake hit Vancouver? Here's what a new report says

Apartment buildings are seen in the West End of Vancouver, on Thursday, January 19, 2023. THE CANADIAN PRESS/Darryl Dyck

If a large earthquake were to strike Vancouver, it could kill or seriously injure more than 1,350 people and severely damage or destroy almost 6,100 buildings, according to a new report.

The 71-page report—authored by city seismic planner Micah Hilt and Dr. Tiegan Hobbs with Natural Resources Canada—will be given to council next Tuesday to inform a future seismic risk reduction plan for Vancouver’s private buildings.

The grim figures are based on modelling software that predicted what would happen in the event a magnitude 7.2 earthquake hits in the Georgia Strait.

According to Natural Resources Canada, the chances of a “very strong” earthquake happening in the area within the next 50 years are one in five.

The hypothetical 7.2 Georgia Strait quake would not only result in over 1,000 casualties and thousands more wrecked buildings; the report says more than 350,000 people would be displaced from their homes for at least three months and direct financial losses would top $17 billion.

A smaller earthquake could still displace up to 25,000 people and kill or severely injure as many as 200, the authors noted.

The study did not account for the subsequent effects of a major earthquake, such as tsunamis, landslides, aftershocks, emergency response delays and fires.

Which buildings are most at risk?

The study identified five general building types that are most at risk of suffering heavy damage and causing long-term displacement. The findings are based on a city inventory of about 90,000 buildings from 2018.

It says nearly 80 per cent of the city’s “seismic risk” comes from these buildings, though they encompass a very small fraction of all buildings in Vancouver. They include concrete mid-and-high-rise multi-unit residential buildings (MURBs); un-reinforced masonry MURBs; wood-framed MURBs; un-reinforced masonry, wood and low-rise concrete commercial buildings; and concrete mid-and-high-rise commercial buildings.

For example, the report says 45 per cent of all displaced individuals, as per the model, would be those living in older wood-framed apartment buildings, a total of 103,900 people. The highest share of “residential casualties” modelled occurred in concrete residential buildings: 40 per cent, or 230 people.

Importantly, the “risk-driving” buildings include the majority of Vancouver’s total housing units, including 80 per cent of purpose-built rentals, as well as SRO buildings, small neighbourhood businesses and offices. Most in danger of partial or complete collapse or becoming uninhabitable are structures built before 1990, with a more dire outlook if they were built before 1973.

“This finding is concerning as existing older purpose-built rental buildings provide relatively affordable housing options in the private market due to their age and longer tenancies,” the report reads.

Where would the damage be the worst?

The riskiest neighbourhoods, the report says, are the West End, the Downtown Eastside, Downtown, Kitsilano, Fairview and Mount Pleasant—areas that hold major employment hubs and more than two-thirds of the city’s purpose-built rental units.

The researchers say census data from higher-risk pockets within those neighbourhoods shows that almost 70 per cent of people are renters, and of them nearly 20 per cent are low-income, more than 10 per cent are seniors, 30 per cent identify as visible minorities and 4 per cent are Indigenous.

“These groups may face additional challenges and structural barriers in preparing their households and recovering from an earthquake, exposing them to potentially greater risk than other residents,” the report reads.

The report also notes that cordoning off highly damaged areas for weeks, months, or even years following a strong earthquake is often required, and that the West End, with its older concrete buildings, and the Downtown Eastside, with its older brick buildings, are at risk of that.

“Cordoning preserves life safety during earthquake response but extends the duration and difficulty of recovery, increasing long-term social and economic impacts,” it reads.

What’s next?

The report concludes by saying a major earthquake threatens the lives, homes and businesses of Vancouverites, adding that most of the city’s affordable housing stock and many small businesses will be permanently lost.

"Overall, a large earthquake is one of the most significant risks to public safety Vancouver faces, but it is a risk that is well understood following detailed risk assessment and analysis,” it reads.

The authors posit that seismic risk reduction can begin with small actions in a limited number of high-risk buildings in particular areas of the city, which are outlined in the report.

“Small actions that quickly build on existing city policies and programs have the added advantage of promoting awareness and positioning the city well to pursue additional senior government funding and tools in support of further, more challenging risk reduction action,” it says.

“The sooner Vancouver begins to take action to reduce risk, even if initially modest, the less challenging it will be to protect residents and ensure recovery in the long term.”

The full report is available online.