The earthquake experiences of local residents help governments prepare for future quakes.
After a tremor, Earthquakes Canada creates a “Did you feel it?” questionnaire on its website.
The 18-question survey asks people to say where they were when the quake occurred, how long the shaking lasted, and asks a number of multiple choice questions such as: “Did pictures on walls move?” and “Did any furniture or appliances slide, tip over, or become displaced?”
A section of the questionnaire
According to seismologist John Cassidy, the information is useful for determining the intensity of an earthquake, which is different from the magnitude.
Magnitude tells the amount of energy released by an earthquake at its source, but it doesn’t directly translate to what people feel.
“What people experience during an earthquake is really important for us as scientists to better understand how ground shaking varies across the region during an earthquake,” Cassidy told the CBC podcast This is Vancouver Island.
The intensity or amount of shaking a quake causes will vary based on distance from the epicentre — and the type of land.
Both Metro Vancouver and Greater Victoria sit on a mix of bedrock and different types of soil — each of which will respond differently to an earthquake.
While scientists have tools to measure the amount of shaking, those tools aren’t in every single building or on every single street — so reports from residents across a region can help bolster that information.
“We have found a very good relationship between what people feel, the actual ground shaking, where we could compare it with real ground shaking recordings from seismometers and with damage,” said Cassidy.
He said it’s also helpful to know if people did not feel shaking.
The information is shared with engineers and other levels of government.
It can be used to help properly design infrastructure like bridges, for example, and to help emergency planners determine which parts of a city will be hardest hit during a major quake.
Easing fears
For people like Jennifer Rowan, sharing such information could also bring peace of mind.
Rowan loves living in Victoria but admits the possibility of a major earthquake makes her think often about moving.
She felt the recent 3.8 magnitude earthquake on Vancouver Island and said knowing she could contribute to research might help.
“I think if I’d be more involved in it, maybe I’d feel better about it. I think actually being part of something is good.”
Rowan said she’ll fill out a report the next time she feels a quake.
To learn more about how researchers use the information from “Did you feel it?” questionnaires and about how Canada’s new earthquake warning system works, listen to the latest episode of This is Vancouver Island:
17:58Did you feel it? Why it helps researchers when you report earthquakes
Every time the earth shakes on the island, we flock to social media to see who else felt the tremor. But did you know you can also report your experience to Earthquakes Canada, to help with future research? Seismologist John Cassidy explains how researchers like him rely on such information. Plus: the latest on the earthquake warning system.
Islanders, this is a podcast for you. Life on Vancouver Island isn’t all sunset strolls and forest bathing — it can be frustrating, isolating and expensive. We’re going to talk about the good, the bad and everything in between. Hosted by Kathryn Marlow every Tuesday.
Tune into This is Vancouver Island every Tuesday on CBC Listen or wherever you get your podcasts.