5.0 magnitude: Rocky Mountain House earthquake upgraded, 2nd largest in Alberta history

A 5.0 magnitude earthquake shook central Alberta Wednesday night.

At approximately 9:23 p.m., Earthquakes Canada reported a 4.1 magnitude earthquake 37 kilometres north of Rocky Mountain House.

That magnitude was upgraded to 5.0 on the Richter scale by Earthquakes Canada on Thursday afternoon.

The upgrade means it was Alberta's second largest on record.

People as far north as Edmonton and as far south as Calgary reported feeling "weak shaking" on Earthquake Canada website's scale of intensity.

#yeg #Edmonton
We just felt a small earthquake in SW Edmonton!!! pic.twitter.com/3vGzzEKxRy

— Chris Jenkins (@dallysix) October 21, 2021

"We’ve had reports of people who felt it out in the Leslyville area, certainly in the Arbutus area," Laura Button from the Town of Rocky Mountain House told CTV News Edmonton.

According to Rocky Mountain House's sewer and water supervisor, no damage was done to any of the town's sewage infrastructure.

"Nothing exciting happened, nothing broke," Doug Fraser said.

The tremors didn’t trigger any system alarms at the water treatment plant, and so far no one has reported any private property damage either.

"We had no complications whatsoever," Rocky Mountain House water treatment plant manager Gary Lewsaw told CTV News Edmonton.

One University of Alberta geo-physicist told CTV News Edmonton that seismic activity in central Alberta has increased in the past decade. According to Jeff Gu, that’s worth studying.

"Some of it was linked to gas production, oil production, and some of them were natural, and then there was an earthquake that was linked to wastewater disposal," Gu said.

Alberta’s energy regulator said Wednesday's earthquake was not connected to wells or drilling.

It pegged the epicentre nine kilometres below the surface, which is typically deeper than human-caused earthquakes.

Rocky Mountain House is approximately 139 kilometres southwest of Edmonton.

With files from CTV News Edmonton's Jeremy Thompson