A major fault in the Yukon, Canada, that has been quiet for at least 12,000 years may be capable of giving off earthquakes of at least magnitude 7.5, new research suggests.

Based on the amount of strain the Tintina fault has accumulated over the past 2.6 million years, it is now under an amount of stress that could lead to a large quake within a human lifespan, researchers reported in the journal Geophysical Research Letters. The finding may require experts to rethink the earthquake danger in the region, the study authors said.

A magnitude 7.5 earthquake would threaten a few small communities within the remote Yukon. But the finding that the Tintina fault may be capable of such a large quake is notable because the fault has been quiet since before the last ice age ended. “Major ancient faults like that can remain as weak zones in the Earth’s crust and then focus ongoing tectonic strain,” Theron Finley, a geoscientist who conducted the research while earning his doctorate at the University of Victoria in Canada, told Live Science.

The Tintina fault is over 620 miles (1,000 kilometers) long and stretches from northeast British Columbia through the Yukon and into Alaska. On its southern end, it connects to the Rocky Mountain Trench fault, which creates a huge valley through southern Canada and northern Montana.

Forty million years ago, during the Eocene epoch, one side of the Tintina fault slid 267 miles (430 km) against the other at a rate of about half an inch (13 millimeters) each year. Today, the fault seems quiet, with only occasional small earthquakes of magnitude 3 to 4 in some sections. However, “there has always been a question of whether it’s still a little bit active or still accumulating strain at a slower rate,” Finley said.