Horizontal drilling involves injecting massive amounts of wastewater to extract oil and gas. And that's been linked in recent years to earthquakes in the United States.

Now, it's becoming a growing concern in British Columbia.

Geological Survey of Canada research scientist told Global B.C. News that there's a "very high" likelihood that recent earthquakes in northeastern B.C. were linked to the fracking of natural gas.

“This is not 100 percent proof," Honn Kao said, "but we are continuing to work with the BC Oil and Gas Commission to get more detailed operation data.”

A 4.5-magnitude quake occurred on November 29 and was felt in Fort St. John, Taylor, Chetwynd, and Dawson Creek, according to Earthquakes Canada. There were also other seismic events that also occurred between 6:27 and 7:15 p.m. on that day.

There were no reports of damage.

On November 30, the B.C. Oil and Gas Commission announced that after the earthquakes occurred, "operations in the vicinity were immediately shut in as a precaution and a Commission investigation is being conducted".

"Mitigation strategies will be examined and put into place for any operations that are linked to the seismic events," the commission reported. 

In the United States, regulators have come under fire for not doing enough to prevent tremors. For more on that, watch the video below.

In 2016, a paper published in Seismological Research Letters highlighted the links between fracking in the Western Canada Sedimentary Basin and earthquakes.

It pointed out that "most recent cases of induced seismicity are highly correlated in time and space with hydraulic fracturing, during which fluids are injected under high pressure during well completion".

"Furthermore," the researchers concluded, "it appears that the maximum-observed magnitude of events associated with hydraulic fracturing may exceed the predictions of an often-cited relationship between the volume of injected fluid and the maximum expected magnitude."