The Alberta Energy Regulator says the order to suspend operations at the Vesta Energy site is a precaution at this time.
Natalie Brodych, communications officer with Alberta Energy Regulator (AER), said at this time the cause of the March 4 earthquake is unknown.
“Vesta Energy reported the earthquake to us, and as a result we ordered the suspension of operations while we investigate,” Brodych said.
Vesta Energy has a site near Sylvan Lake and reported it was fracturing at the time of the quake. Operations at the site immediately ceased, according to an AER order.
Brodych says AER is working with the Alberta Geological Survey to investigate whether or not work at the Vesta Energy site was the cause of Monday’s 4.6 earthquake.
“To investigate the earthquake, the AER and Alberta Geological Survey (AGS) are reviewing the passive seismic data (natural, low frequency earth movements) recorded in the region alongside operational data to look for possible correlations,” said Brodych.
According the AGS, the epicentre of the earthquake is believed to have been in close proximity to the Vesta Energy site.
Director of Environment and Operational Performance Erik Kuleba says in the order issued to Vesta Energy “that a release of a substance or substances has occurred, and
that substances have caused, are causing, or may cause an adverse effect.”
“We have very strict requirements, and a number of requirements that are in place should something like this happen,” said Brodych. “While we do not know for sure the fracturing is responsible it is something we are required to look into.”
Before they are able to resume operations, Vesta Energy must submit a plan to AER by March 11 “to show how they will minimize the risk of any seismic impacts in the future.”
Vesta Energy must include in their plan all passive seismic data from April 2018 to present.
“The AGS will also investigate the subsurface conditions in the area to determine if they are vulnerable to induced seismicity,” explained Brodych.
According to the AGS, Alberta has experienced more than 600 earthquakes between 1985 and 2011. During the same time, Saskatchewan only experienced 41 recorded earthquakes.
Most of Alberta’s recorded earthquakes are distributed evenly along the foothills and Rocky Mountains, there are also clusters of earthquakes east of the Rocky Mountain “deformation belt” around Rocky Mountain House, according to AGS.
“The Rocky Mountain House cluster studies documented the first evidence of induced seismicity related to hydrocarbon production in Alberta,” the AGS website states.
The AGS says areas that are generally considered to be more “seismically quiet” have been “tentatively linked to hydraulic fracturing operations.”
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