Fracking operations should proceed with caution in gas-rich northeastern British Columbia, with recent research into last November’s fracking-induced 4.5 magnitude earthquake near the Site C dam site revealing underground rock seams in a hair-trigger state—needing only a small injection of fracking fluid to induce “seismicity”.

In August, eight months after the BC Oil and Gas Commission determined that the 4.5 quake and several smaller ones were caused by injections of fracking fluids at a drilling site south of Fort St. John, a preliminary geological study found that the “underground rocks in the gas-rich area, between Dawson Creek and Fort St. John, are in a ‘near critical state’,” CBC reports.

Research lead, geophysicist, and oil and gas consultant Amy Fox said the aim of the preliminary study, the first in an ongoing series, was to help oil and gas companies to operate more safely. “Companies aren’t just going in there and…hoping they don’t have an earthquake,” she said. “They’re actually assessing the risk and perhaps leaving some areas alone where they think…something might happen.”

While fracking isn’t itself producing the fault lines that lead to quakes, Fox told CBC, it’s accelerating a natural process—or aggravating a natural fault. “These faults exist because of millions of years of geologic history,” she said. “We are just speeding up a natural earthquake that would have occurred at some point anyway.”

But Ben Parfitt, resource policy analyst with the Canadian Centre for Policy Alternatives, called the findings “a wakeup call” that “almost certainly means more earthquakes ahead.”

The CBC reports that while “most fracking doesn’t trigger earthquakes, 90% of the earthquakes in northeastern B.C. are caused by fracking,” adding that “as multi-billion-dollar LNG [projects] proceed, fracking is expected to increase dramatically in northeastern B.C.”