Vancouver earthquake scenario predicts up to 10,000 casualties

Roughly 10,000 people in the Lower Mainland might die if a shallow earthquake struck directly beneath the city of Vancouver — that's the projection from a worst-case scenario in the provincial government's Earthquake Immediate Response Plan.

That number — combined with the recent windstorm in Southern B.C. — has the minister responsible for emergency preparedness in B.C. concerned that many are not prepared for the possibility of a large earthquake.

The scenario, laid out in a report released at the end of June, describes the event occurring on an ordinary January day, following a few days of continuous heavy rain that has caused some flooding.

The downtown cores of the region's cities are full, and many parents and caregivers are on the road after having picked up children from school early to avoid traffic delays in the wet weather.

Then suddenly, a rumbling sound like a freight train is heard, followed by 10 to 20 seconds of violent shaking.

The scenario goes on to describe roads cracking, buildings collapsing, and fires starting through damaged electrical power and gas lines.

Impact on Victoria modeled

Two separate earthquakes, both shallow, were modeled for the report.

For the Greater Vancouver region, the earthquake was based on the largest historical earthquake in the region, a magnitude 7.3 earthquake which took place on Vancouver island in 1946.

In the second scenario a magnitude 7.0 earthquake was modeled for the Greater Victoria region, based on an existing fault that has not been active in the last 10,000 years.

"Both of these separate events have the potential to occur, although the probability is low," the report said.

"These represent the worst-case scenarios for an earthquake affecting B.C. due to injuries, damage, and greatest economic impact."

The anticipated effects include 52 injuries per 1,000 people in the Greater Victoria area (or Capital Regional District) and Metro Vancouver, and 4 casualties per 1,000 people.

The report goes on to detail how the province would work with various jurisdictions to coordinate an emergency response plan.

Minister is worried

Naomi Yamamoto, B.C.'s minister of state responsible for emergency preparedness, said these are "huge numbers."

"I'm quite concerned that most people aren't prepared, as evidenced by the recent windstorm [in southwestern B.C.]"

Yamamoto said the province will increase efforts to make British Columbians more aware of earthquake preparedness.

She said the province will continue to spend money to seismically upgrade schools, hospitals and other buildings, as well as roads and bridges.

In March 2015 it was reported that a deadline announced a decade ago to upgrade all the province's schools by 2020 was pushed back between five and 10 years for various districts.

When asked if this new scenario would motivate the government to speed up that time frame, the Yamamoto replied that a number of projects require seismic upgrading.

"We never know when an earthquake will occur," she said.

"It could be in the middle of the night, it could be on a weekend, it could be tomorrow. So schools are important, but so is the importance of seismically upgrading our highway systems and bridges. We also need to make sure that emergency vehicles can actually get to hospitals."

Numbers are not surprising

Carlos Ventura, the director of the earthquake engineering research facility at the University of B.C., said other studies have previously showed that this extent of damage is possible.

"This is what you might expect for a region with a population that we have here," he said.

"So the numbers are not unrealistic. They are scary numbers, but it's good to know what could happen it we don't take steps to protect ourselves and minimize the potential damage from an earthquake."

Ventura said a major concern for the region is the number of older brick buildings, which are more likely to collapse in a severe earthquake, as well as buildings built in the 1960s or 1970s with concrete that doesn't meet today's standards.

The report forecasts that 12 per cent of buildings in Metro Vancouver region are most likely to receive complete damage, compared to 11 per cent in the Greater Victoria area.

However, he added that many buildings in the region have been designed to withstand earthquakes — and instead the threat of injury could come from falling or flying objects inside the building.

"The major problem we have is to fix the interior of buildings, to prevent those kinds of injuries to people," he said.

Yamamoto said that the recent windstorm in B.C. has highlighted the importance of people being able to access information during an emergency, and being prepared.

"We need to make sure that people have emergency kits on hand. We need to make sure that the kits provide enough water for at least three days, food for thee days, batteries, and hand-powered, hand-cranked flashlights."

To hear Minister Naomi Yamamoto and UBC professor Carlos Ventura on B.C. Almanac, click the audio labelled: New report predicts impact of earthquake in Vancouver