Alberta Energy Regulator is probing whether fracking caused an earthquake that rattled the Sylvan Lake and Red Deer areas on Monday morning.
“We are currently reviewing the events to determine if the incident is due to hydraulic fracturing activities or natural causes,” said AER spokesperson Natalie Brodych. “Vesta Energy was conducting hydraulic fracturing activities in the area, but has since stopped.”
Brodych said the earthquake was detected about 12 km south of Sylvan Lake and was reported to the regulator by Vesta Energy at 6:20 a.m.
There have been no reported impacts to public safety, infrastructure, or the environment, she said.
Vesta Energy said in a statement Monday afternoon that its monitoring equipment detected a 4.32 magnitude seismic event at 5:56 a.m. about 20 km southwest of Red Deer.
“There were reports of power outages in the region that may have resulted from the seismic event,” says the company. “Vesta has shut down its completions activity in the area and is working with the Alberta Energy Regulator to review and investigate the situation.
“Safety of the public and our employees is paramount at Vesta Energy. The company has real time seismic monitoring equipment on site which will be used in its investigation of the situation.”
The company says it will release further information as it becomes available.
A 4.6 magnitude earthquake that shook homes and spooked many central Albertans was the largest ever to hit the area, says Natural Resources Canada.
Taimi Mulder, an earthquake seismologist with the Geological Survey of Canada says the most powerful earthquakes in central Alberta usually top out at 3.8 to 4 on the Richter scale.
Normally earthquakes that sit on the higher end of the scale for Central Alberta are around 3.8-4 on the Richter scale.
“We are still classifying this as a light earthquake, but it does seem to be the largest to hit the area,” said Mulder.
The quake occurred around 5:55 a.m. local time Monday and was lightly felt in Red Deer, Sylvan Lake and Lacombe. The earthquake originated about a kilometre below the surface.
Mulder said the event is still being investigated, but it does not appear to be caused by fracking in the area.
The cause is believed to be from tectonic movement along the Rocky Mountains.
While Central Alberta is a distance away from a fault line, quakes still occur every few years.
“It is very unusual, but not unheard of to have an earthquake in the area,” Mulder said adding, “Normally we see more activity in larger centres such as Calgary, Edmonton or Banff.”
AltaLink spokesman Scott Schreiner said about 5:55 a.m. a signal from a substation just south of Sylvan Lake indicated a problem.
“It indicated we had lost two transformers there that had tripped out of service.”
About 4,600 customers were affected. Some got their power back within eight minutes but others had to wait until just before 7:30 a.m.
Schreiner said the electricity transmission system is designed with safety mechanisms that are triggered when any anomalies are detected.
All of the customers are being served by one transformer and technicians are checking the second to ensure there was no damage before it is brought back into service.
Schreiner said they can’t say for sure the earthquake caused the problem.
“Not conclusively. I think it’s a reasonable assumption to say that it is related to the earthquake but the investigation is ongoing.”