People in the area got quite a surprise on the evening of Nov. 29. A series of earth tremors caused buildings to briefly shake, objects to rattle on shelves and so on.

From what we’ve heard (and experienced) most people initially looked for other explanations. A gust of wind? A big truck passing on the street? A snowplow? A train?

But it turned out to be an actual earthquake, with aftershocks.

The first one happened at about 4:45 p.m., the next a few minutes later. About an hour after that, a much bigger shock. Then another, smaller one, at about 7:55 p.m.

“My whole building was just shaking!” says Perri Walker, who works at The Leader.

According to reports, one of the tremors measured 5.8 on the Richter Scale, making in the strongest quake ever recorded in Alberta. The epicentre of the quake (or series of quakes) was near Reno, a hamlet located about 40 kilometres southeast of Peace River. Also reported was the fact there had been three milder tremors recorded in the same area over the previous few days.

The Alberta Energy Regulator, perhaps anticipating the question, was quick to announce there has been no active hydraulic fracturing in the area.

The environmental organization Keepers of the Water, on the other hand, gives a very different impression. In a Dec. 1 news release, it called for an independent investigation to determine the cause. Keepers points the finger straight at the CNRL Carson (or Carmon – both names are used) heavy oil project in the area. It speaks of “massive amounts of hot water injected,” which it says suggests “a direct industry cause of these earthquakes.”

Alberta’s previous strongest recorded quake was back in 2001, at 5.4 on the Richter Scale. It was located northeast of Dawson Creek, B.C.

According to Joseph Farrugia of Natural Resources Canada, the Richter Scale measurement is not necessarily accurate, and may change. But he confirmed in a phone interview (from Victoria B.C., where he said they are expecting a 9.0 quake one of these years) that if the 5.8 is correct, it would in fact be the strongest ever recorded in Alberta.

Farrugia also said seven aftershocks from the Nov. 29 quake have been recorded, so far, and more are likely.

“They’ll probably taper off in the coming days,” he said, on Dec. 1.

Alberta is more or less in the middle of a continental plate, Farrugia explained, so it’s not a case of plate edges rubbing against each other. But stress does build up and extend far into the middle of the North American Plate. When the stress exceeds the friction along fault lines, quakes happen. They’re called ‘intra-continental quakes,’ he said.

Alberta actually gets quite a few of these, though the further from the mountains, the fewer there are.

Earthquakes recorded in (or near) Alberta in the past 10 years, with the Nov. 29 one near Reno Alberta in purple.
Image courtesy of Natural Resources Canada.

by Joe McWilliams

December 5, 2022

This item copyrighted by   TheRegional.com / Lakeside Leaader   Slave Lake, Alberta

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