Ryan Thoms – “The 1946 Vancouver Island Earthquake”

The headlines were impressive
– Powell River News

But the damage was relatively light
– Powell River Museum and Archives

Vancouver Island suffered greater damage. This is the Elementary school in Courtenay. Fortunately it was a Sunday so kids were at home.
– Powell River Musuem and Archives

Here’s the post office in Courtenay.
-Powell River Museum and Archives

And this is the Bank of Montreal in Port Alberni
– Powell River Museum and Archives

The epicentre was in Forbidden Plateau, and at magnitude 7.3 it was a “pretty good shake”. felt from the Okanagan to Portland
– Natural Resouces Canada

It was likely a “strike-slip” earthquake
– Natural Resouces Canada

although it remains unclear which of the numerous fault-lines in the region was the culprit
– Natural Resouces Canada

There were numerous reports of “liquefaction”, “underwater slumping” and “fill in slumping”. Yes it was a “good shake”.
– Natural Resouces Canada

I thought the big underwater slump just off Grief Point to be particularly noteworthy
– Mosher et al. 2004

The fact are clear.
– R. Thoms

and some of the eyewitness accounts are impressive
– R. Thoms

but it could have been worse
– R. Thoms

Take heed
– R. Thoms

Ryan Thoms – “The 1946 Vancouver Island Earthquake”
by Andrew Bryant, 21 Oct 2021.

After many years with the BC Wildfire Service, Ryan Thoms now lives in Powell River and is manager of the qathet Regional District’s Regional Emergency Preparedness Service.

His topic was apt, for not many remember the Vancouver Island earthquake of 1946.  Fortunately the local damage was not severe.  Some chimneys were toppled, and the school was damaged.  But residents were fortunate.  The fact that it happened at 10:13 AM on a Sunday in June meant that most people were home.  Had it occurred on a weekday in January things might have been quite different.

Beginning with historical images and newspaper accounts, Ryan took our understanding of the event to a new level with application of modern geophysical methods.  There were a few surprises.  I was unaware, for example, that there was a freshwater tsunami on Powell Lake, and a substantial “debris flow avalanche” just off Grief Point.

History is indeed surprising…and please take warning…often repeats itself!