earthquake near Fort St. John, B.C.
© Google MapsThe location of the Nov. 29, 2018 earthquake near Fort St. John, B.C.
An earthquake that struck northeastern B.C. on Thursday evening was "very likely" caused by fracking, a preliminary investigation has found.

Earthquakes Canada said the quake had a preliminary magnitude of 4.5, with the epicentre about 16 kilometres southwest of Fort St. John.

It hit around 5 p.m. PT, followed by another tremor of similar magnitude, classified as an aftershock, less than an hour later.

The Geological Survey of Canada and the B.C. Oil and Gas Commission launched an investigation to figure out what caused the tremor.

On Friday, a statement said they had confirmed there was active fracking happening near the epicentre when the quake struck.

"The likelihood this was induced ... there's a very high correlation," said Honn Kao, seismology research scientist with the Geological Survey of Canada.

Kao stressed the link was a preliminary finding and more investigation is required before the agency confirms the quake was "100 per cent" a result of fracking - but said it's "very likely" that's the case.

Hydraulic fracturing - or fracking - is the process of injecting water, sand and other chemicals underground at a very high pressure to fracture shale rock, in order to extract natural gas.

Western Alberta and northeast B.C. have a high rate of fracking-induced earthquakes, according to a study from the University of Alberta.

Tremor 'lightly felt'

People in Fort St. John, as well as Taylor, Chetwynd and Dawson Creek, reported feeling the earthquake on social media, but there are currently no reports of damage.

Kao said early data suggests the quake had a relatively shallow depth, which is likely why the quake was widely felt.

"This is certainly an event that has been felt quite a bit by the local residents," Kao said. "Although this is a significant event for the region, I don't think it's going to cause significant damage."

According to the U.S. Geological Survey, the quake had a preliminary magnitude of 4.2.

With files from Johanna Wagstaffe and Rhianna Schmunk