An earthquake near Rocky Mountain House on Wednesday night could be felt as far away as Edmonton.
The 4.1 magnitude earthquake was detected at 9:23 p.m. 37 km northwest of Rocky Mountain House.
There have been no reports of damage from the quake.
Alberta Energy Regulator (AER) and its Alberta Geological Survey (AGS) branch said it was aware of the earthquake and it is not oil industry-related.
“The earthquake occurred at approximately 9 km below the surface, which indicates that it occurred naturally,” said the AER in an email.
“In Alberta, earthquakes that are induced by energy development typically occur between four and five km below the surface.”
Earthquakes Canada had received more than 400 reports on the earthquake by Thursday morning. Of those, 369 reported the effects as weak and another 35 described it as light, using Earthquakes Canada 10-level scale, which ranges from not felt at all (1) to extreme with heavy damage (10).
More than 1,000 people shared their experiences with Wednesday’s quake on volcanodiscovery.com.
A Red Deer resident wrote, ” I was laying on my bed, and it felt like the building was hit by a car or something. my bed shook as if I had jumped on it”
“Sitting in chair in living room of mobile home. Felt floor shake for a few seconds. felt like I was falling backwards in the chai,” wrote someone, who identified themselves as being near Rocky Mountain House and who was located 36 km southeast of the epicentre.
Another Rocky resident 42 km south of the epicentre wrote, “Inside the house. Heard a rumble and then felt bed move slightly and shake for a couple of seconds. Heard noises of things in house moving.”
A Red Deer resident about 90 km southeast of the epicentre reported, “It felt as though something hit the roof, and as if the wall behind the bookcase moved. It freaked me out and I said, ‘What was that?’”
Another Rocky resident, 45 km south of the epicentre, said “Was sleeping but thought someone broke in the back door. My dog barked and took off. My partner said it felt like a truck hit the house.”
A Red Deer County resident living about five km east of Spruce View and 86 km from the epicentre wrote, “I ran outside thinking someone had run into our house with a heavy vehicle. My neighbour a 1/4 mile away didn’t feel anything.”
Some from as far away as Edmonton, Three Hills, Trochu reported mild shaking.
On March 4, 2019 a 4.18 magnitude earthquake near Sylvan Lake rattled some windows in central Alberta.
The AGS undertook an investigation shortly after the quake, whose epicentre was about 12 kilometres south of Sylvan Lake.
Fracking was later confirmed as the cause of the earthquake that rattled homes from Sylvan Lake to Red Deer last March, say government scientists. the investigation also determined that a 3.13 magnitude quake near Red Deer in March 2018 was “induced,” as was a cluster of seismic events under 2.0 on the Richter scale.
Calgary-based Vesta Energy was fracking in the Sylvan Lake area when the 4.18 magnitude quake was triggered.
In May 2020, Vesta was given the green light to resume fracking at sites considered low risk for seismic activity after the Alberta Energy Regulator signed off on a risk assessment plan.
The incident led to new seismic monitoring and requirements for all companies fracking in the Red Deer region.