The earthquake and subsequent tsunami warning for coastal British Columbia on Jan 23, had a lot of Squamish residents wondering if we would ever have to worry about a tsunami here.
The answer is “no” and “maybe a little.”
Had the tsunami materialized after the magnitude 7.9 earthquake in the Gulf of Alaska, the waves would not have reached us.
“The tsunami would almost completely disappear around the Gulf Islands,” said Brett Gilley, professor in the Earth Science department at the University of British Columbia. “It basically has to turn the corner while simultaneously traversing all those islands and the models suggest we wouldn’t have anything impactful within the Salish Sea because of that.”
But Squamish may be impacted by a tsunami were one to generate within the Salish Sea, either from a large rock fall or an underwater landslide off of Richmond, Gilley added.
“Those could generate tsunamis that might be more of a concern,” he said, adding there are deposits on the Gulf Islands that are evidence of these scenarios happening at some point.
“So if a tsunami generated in the strait and if it went up Howe Sound then it could concentrate as it hit Squamish,” he said.
It is unlikely that this type of tsunami would be as powerful as the earthquake- generated ones, Gilley added.
A tsunami is basically a flood, Gilley explained.
“They are basically a really high tide for 20 minutes,” he said. “And then it flows out again and what is dangerous with that is you are being caught in a big river. One of the things with tsunamis is people are in the water and being hit by debris.”
Squamish residents will never have to be as concerned as people who live in more open coastal areas, such as Port Alberni.
But there are other worries such as landslides, of course.
“There’s nowhere safe on the earth,” Gilley said, adding when people ask him how he can live on the coast with the earthquake risks, he points to Saskatchewan and says, “tornadoes.”