Fracking site shut down after earthquake shakes Fox Creek, Alta.

A hydraulic fracturing op‐ eration near the commu‐ nity of Fox Creek in north‐ western Alberta has been shut down after an earth‐ quake last week.

The tremor, recorded Friday afternoon 35 kilome‐ tres southwest of the town, triggered a shutdown of a nearby drilling site and a re‐ view by the Alberta Energy

Regulator.

According to Natural Re‐ sources Canada, the quake was recorded just before 4:30 p.m. at a depth of 5.8 kilometres. It registered at a preliminary magnitude of 4.4.

There were no reports of injury or property damage and the earthquake was likely not felt by residents of Fox Creek, a town about 265 kilometres northwest of Ed‐ monton.

Cygnet Energy, a small Calgary-based firm, reported the quake near one of its well sites.The company was or‐ dered to stop all operations on the well pad and has done so safely, the regulator said.

In a statement, the regula‐ tor said seismologists with the Alberta Geological Survey have confirmed that Friday's seismic event was from nat‐ ural causes but induced by industrial activity.

As of Wednesday, the well site remained shut down. The regulator said hydraulic fracturing work was being done on the site as recently as March 17.

Brindley Smith, a seismol‐ ogist with Natural Resources Canada, said hydraulic frac‐ turing operations are a known trigger for seismic ac‐ tivity. Hydraulic fracturing, or fracking, is intended to create disturbances underground in order to release gas from shale formations.

The method for extracting natural gas involves injecting fluid into a well under high pressure to fracture the gasbearing rock and release the gas inside.

The practice puts pres‐ sure on existing fault lines in Earth's crust and can cause them to slip, Smith said.

"This is an area where you could have industrial activity such as wastewater fracking or injection and that can lead to earthquakes," Smith said in an interview Tuesday.

"Fox Creek has always been well known as an area that sees induced seismic ac‐ tivity."

Friday's quake is the latest in a string of tremors recorded in the area.

In a 50-km radius around the epicentre of Friday's tremor, 25 seismic events have been recorded since the beginning of this year.

"It does look like it has picked up and I would just expect it's because they may be ramping up activity in the area," Smith said.

"It could be something we may see it die down again in a matter of just weeks. It's hard for us to say because we can't really predict how activity will occur."

Investigation continues

Under the Alberta's trafficlight system for preventing industry-caused earth‐ quakes, the AER automatical‐ ly shuts down a fracking site when an earthquake hits a magnitude of 4.0 or higher in the area in which a company is operating.

Operations can't resume without the regulator's ap‐ proval.

Cygnet Energy has yet to comment.

The AER said it will work with scientists at the Alberta Geological Survey to investi‐ gate.

Jeff Gu, a geophysicist with the University of Alber‐ ta, said the event will likely trigger renewed research on the quake's potential link to previous clusters and indus‐ trial activity in the area.

After years of relative calm, seismic activity sur‐ rounding Fox Creek has pick‐ ed up.

"There's going to be studies focusing on this par‐ ticular event," Gu said. "It's a significant magnitude, but it's certainly not the biggest we've seen in Alberta."

The Fox Creek area and its fracking-caused quakes have long been the focus of re‐ searchers and regulators in Alberta.

Fracking has been linked to most large earthquakes in Alberta in recent decades.

One of the largest occur‐ red in 2016 just west of Fox Creek and was measured at 4.8 magnitude. It was so strong that it was felt in St. Albert, 280 km away.

Alberta had been histori‐ cally quiet in terms of seismic activity before fracking activ‐ ity began ramping up. Fox Creek recorded many of the first notable clusters, Gu said.

Gu said those clusters triggered changes in Alberta's regulatory system and wide‐ spread research aimed at managing the risk of indus‐ try-caused tremors.

"Fox Creek is really one of the first high-profile areas in the Alberta that really alerted people to the issue of in‐ duced earthquakes," Gu said.

"Fox Creek was kind of the catalyst."