It takes only seconds to save lives
By 2024, more than 10 million people in Canada in the most earthquake-prone regions of the country will be able to receive Earthquake Early Warning (EEW) alerts, providing a few precious seconds to take action.
October 2021
Did you know there are more than 5,000 earthquakes in Canada every year? Only about 50 of them result in the ground shaking vigorously enough to notice; even fewer result in any destruction. But when there is serious shaking, it can be fatal.
“The national EEW system will give advance warning up to tens of seconds. It doesn’t sound like a lot of time, but it’s enough to save lives and potentially reduce damage,” says Alison Bird, an earthquake seismologist with Natural Resources Canada (NRCan). She’s part of a team of scientists and technicians installing a national network of about 400 seismic sensors as part of a national Earthquake Early Warning system. It uses advanced, automated software and the latest technologies to estimate — in real time — how much shaking an earthquake might cause and sends out alerts instantaneously.
Summer 2021: (l-r) Seismic equipment is first tested and calibrated in a laboratory in Ottawa. Fieldwork assistants come in various shapes, sizes and furriness. Here, Maverick the dog is on duty as his person Reid Van Brabant goes to collect vibration data near Highway 417 in Ontario. Canadian Hazards Information Service technologist Mingzhou Li surveys a potential station site in B.C.
Historic megathrust earthquake
To understand how valuable Canada’s EEW system might be, go back to January 27, 1700. That’s when a powerful magnitude nine (M9) megathrust earthquake ruptured roughly 1,000 kilometres of the Cascadia Subduction Zone along the Pacific coast, from mid-Vancouver Island to northern California. It generated incredible shaking, landslides and a huge tsunami. Indigenous knowledge tells us it changed the way First Nations in the region planned their communities. They moved their communities inland, away from the shoreline.
Fast forward 300-plus years, the area is now home to millions of people, some living in waterfront communities. There are tunnels, bridges, ferries and shipping vessels that criss-cross over busy waterways. If a megathrust earthquake like that happened today, it would be devastating. Soon, the EEW system could give most people in the area 30 to 60 seconds of warning.
There is a greater likelihood, however, of experiencing other types of strong damaging earthquakes at various points in this region: within the North American Plate, on which we live; within the subducting Juan de Fuca Plate; and along other major faults, such as the Queen Charlotte Fault along the west coast of Haida Gwaii. For these areas, the EEW alert would provide seconds to tens of seconds of warning.
Automated alerts could save hundreds of lives
A few seconds is enough time for someone to drop, cover and hold on, or if they’re driving, pull over and apply a parking brake. The benefits of the EEW, however, could potentially save hundreds of lives. “With this EEW system, critical infrastructure operators can have technology in place whereby the alert automatically triggers protective actions,” says Alison.
Signals could prompt infrastructure safety systems to take action automatically, such as:
- Triggering trains to slow down
- Stopping traffic from driving onto bridges or into tunnels
- Diverting incoming air traffic
- Allowing surgeons to stop surgery
- Closing gas valves
- Opening fire hall and ambulance bay doors
Earthquakes are often associated with Canada’s West Coast, but there are other vulnerable zones, primarily in eastern Ontario and along the St. Lawrence River in Quebec.
Canada’s earthquake zones, not just the West Coast
In Canada, most of the earthquake risk is concentrated along the B.C. coast, which is on the Ring of Fire, a very active seismic and volcanic region stretching around the edge of the Pacific Ocean, including New Zealand, Chile, Japan, Canada, the western United States and Mexico. It’s where most of the Earth’s major earthquakes occur.
If you live elsewhere in Canada, that doesn’t mean you’re out of danger. “There are significant seismic risks that exist along the Ottawa River valley up through Montreal and the St. Lawrence Seaway,” says Alison. “They might not register as high on the magnitude scale, but they can cause significant damage, especially to older masonry structures. Also, because the crust is denser in the east, the seismic waves retain their strength to greater distances, and as a result they impact a greater area.”
It’s not a matter of if, but when
Being prepared to take action in a cool, calm and collected manner will be crucial for the EEW to be effective. “The whole idea is not only to alert people, but to ensure individuals know the best course of action to take,” says Alison. “In stressful situations, it can be hard to think clearly, and too often it becomes fight or flight as people exit buildings,” she adds. “Which is one of the worst things you can do in an earthquake. By practising the drop, cover and hold on technique, like during October’s ShakeOut earthquake drill, you can help create the muscle memory that will take you to a safe space during an earthquake.”
Earthquakes release energy that travels through the Earth as seismic waves. Seismic sensors detect the first energy to radiate from an earthquake, the P-wave, which rarely causes damage. The sensors transmit this information to data centres where a computer calculates the earthquake's location, its magnitude and the expected ground shaking across the region. This method can provide seconds to tens of seconds of warning before the arrival of secondary S-waves, which bring the strong shaking that can cause most of the damage.
Most earthquakes in B.C., eastern Ontario and southern Quebec tend to occur closer to populated centres, which reduces the warning time from a few seconds to about 30 seconds. And it might not be possible for the warning to arrive before the strong shaking in areas close to the earthquake’s epicentre; this is referred to as the Late Alert Zone.
How does an EEW system work?
Earthquakes release energy that travels as seismic waves through the Earth’s surface in all directions, similar to sound waves. The first waves are P, or primary waves; they travel quickly, followed by the S, or secondary waves, which are slower and much more damaging.
The sensors — each about the size of a shoebox — will detect the first P-wave energy to radiate from an earthquake and then instantly transmit a signal to the data centres. The system uses software from the United States Geological Survey (already proven in California, Oregon and Washington), to analyze the seismic data to determine the location and magnitude of the earthquake. It also estimates how intense the ground shaking might become in the region. These sensors can detect significant earthquakes so quickly (within a few seconds), alerts can reach many people before the S-waves arrive.
Looking to the future:
A small, dedicated team at NRCan is working on this system, with the help of provincial, territorial and municipal governments, First Nations, critical infrastructure operators, and other enterprises, such as BC Ferries, which will host several sensors at its terminals along B.C.’s coastline.
In the future, if you live in one of Canada’s earthquake zones and receive an EEW alert, remember this: drop, cover and hold on until all shaking stops.
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