News » Environment

Earthquake science has advanced, but there's no predicting the 'Big One'

Preparation is key for populations in active earthquake zones



The largest earthquake ever recorded in the Whistler area happened more than half a century ago and measured at a magnitude 5.

"That was on January 30 of 1942," said John Cassidy, a research scientist with the pacific branch of the Geological Survey of Canada.

"So if anyone felt it and has information, they can pass that on to us, because we don't have a lot of information for that particular earthquake."

The technology used to track and measure earthquakes has come a long way since 1942, to the point that Whistler even has its own seismologic equipment measuring every slight tremor.

You can track its findings in real time at

"In the past year, we've recorded 98 earthquakes within 100 kilometres of Whistler... most of those are west of Whistler in the Coast Mountains," Cassidy said.

"If you zoom in to say within 25 kilometres of Whistler, there have only been six earthquakes in the past year, and none of those were felt."

Even with advances made to technology, the reports of what people felt during an earthquake are put to good use.

"We can use that information to get a better location, a better idea of whether it was a really deep earthquake or a shallow earthquake, and the magnitude of the earthquake," Cassidy said.

"Felt" information, as it's called, goes back hundreds of years, to the days of early European explorers and the annals of First Nations oral histories before that.

"Earthquake science is relatively young... we've been recording earthquakes for about 100 years, but with really primitive instruments until about 30 years ago," Cassidy said.

But the rise of digital instruments in recent decades has given researchers a wealth of new precision and detail.

"You can start looking for alignments of earthquakes, looking for faults," Cassidy said.

"During large earthquakes you can actually map out how the fault moved, and how much it slipped."

Researchers locate about 4,000 earthquakes on Canada's West Coast every year, said Alison Bird, earthquake seismologist with the Geological Survey of Canada.

"Things are constantly improving in terms of the technology," Bird said. "They're getting faster, smaller, more efficient."

The Geological Survey is currently working with stakeholders to develop an early warning system both for earthquakes and tsunamis, Bird said.

The system would be built around "P-wave detectors" placed in locations like schools or hospitals that would detect the first wave of an earthquake (known as the primary or pressure wave).

"It gives you time to get underneath your desk hopefully before the S-wave arrives, which is the secondary or shear wave," Bird said.

"That's the stronger wave, the strong side-to-side motion. The one that generally causes most of the damage in an earthquake is the S-wave."

Having the early detection could make all the difference in key situations — like for a person cooking with a gas oven or a doctor performing surgery — Bird said.

"It's amazing actually how much you can do in five seconds," she said.

It could be five-to-10 years before the West Coast has a robust early warning system in place for earthquakes and tsunamis, but the technology could also expand on a person-to-person level, Bird said.

"Eventually it's very feasible for you to have a little alarm built into your cell phone," she said.

It's impossible to accurately predict exactly when and where a quake will strike, but using past data researchers are able to make educated guesses.

Over the next 50 years, there is roughly an eight-to-10-per-cent probability of an "intensity 7" earthquake in the Whistler area, Cassidy said.

During an intensity 7 earthquake, not to be confused with a magnitude 7, which would be much bigger, people could expect to experience a "frightening shaking level," Cassidy said.

"It would cause damage to old structures but it wouldn't be very damaging. It wouldn't really cause damage to modern or well-engineered structures."

But while researchers can't pinpoint when and where the next big earthquake will strike, their work is crucial for updating building codes and keeping the public informed.

"The big earthquakes, they strike without warning, and that's a real challenge," Cassidy said. "So we need to be prepared now for something that could happen this afternoon, or it could happen in 10 years or in 50 years, but it will happen at some point."

Add a comment