An extended-overlooked geologic fault in Canada’s distant north could also be able to producing an enormous earthquake, based on new analysis.
The Tintina Fault, stretching about 620 miles (1,000 kilometers) from British Columbia to Alaska, was as soon as regarded as inactive for at the very least 40 million years. Now scientists say it has a historical past of huge ruptures throughout the final 2.6 million years and will accomplish that once more.
The research, led by researchers on the College of Victoria (UVic) recognized an 81-mile (130-km) part of the fault close to Dawson Metropolis the place a number of previous quakes have left their mark on the panorama. The crew used high-resolution topographic knowledge from satellites, plane and drones to detect fault scarps, slender ridges shaped when the bottom shifts throughout an earthquake, that had been beforehand hidden beneath dense forest and glacial deposits.
“Lidar and satellite tv for pc knowledge are extremely vital for this sort of work, and have revolutionized the sphere of paleoseismology,” lead creator Theron Finley informed House.com in an e-mail. “There are numerous different circumstances in Canada and past the place beforehand unrecognized faults have been found because of this know-how.”
Proof of historical, highly effective earthquakes
By measuring how far landforms have been displaced, scientists pieced together the fault’s recent activity. Glacial features 2.6 million years old have shifted sideways by about 0.62 miles (1 km), while features 132,000 years old are offset by 246 feet (75 meters). Significantly, features just 12,000 years old show no displacement at all.
This long, quiet period is not necessarily good news. Based on tectonic strain rates of about 0.008 to 0.03 inches (0.2 to 0.8 millimeters) per year, researchers estimate the fault has built up about 20 feet (6 meters) of slip deficit since its last major earthquake.
“Though our observations indicate a substantial slip deficit, we don’t yet have a good sense of how frequently large ruptures occur on the Tintina fault,” Finley said. “At this point we can’t really say whether another rupture is likely in the short term, or in thousands of years.”
To gain a better understanding of how often large earthquakes strike the Tintina fault, Finley said they plan to excavate a paleoseismic trench across it. This would allow the team to examine offset sediment layers and date past quakes, providing a clearer picture of the fault’s recurrence rate.
How the fault moves
The Tintina fault is a right-lateral strike-slip fault, the same type as California’s San Andreas fault, meaning the two sides of the fault grind past each other horizontally. This kind of fault can produce sudden, powerful shifts of several meters in a single event, releasing enormous amounts of stored energy.
But Finley stressed that while the Tintina fault extends about 620 miles (1,000 kilometers), the largest strike-slip ruptures in the world rarely exceed 186 miles (300 kilometers). “The entire length of the fault would not rupture all at once,” he said. “However, our findings do motivate further scrutiny on other sections of the Tintina fault that might also prove to be active.”
Risk to the Yukon and beyond
The team’s analysis suggests a rupture on this section of the Tintina fault could exceed magnitude 7.5, strong enough to cause severe shaking in Dawson City, damage highways and mining operations, and trigger landslides. The Moosehide and Sunnydale landslides near Dawson City already show signs of instability.
Despite this, the Tintina fault is not currently listed as a separate seismic source in Canada’s National Seismic Hazard Model (NSHM), which informs earthquake building codes and engineering standards. These findings will be incorporated into future updates and shared with local governments to improve emergency planning, according to the press release.
This research was published July 15, 2025, within the journal Geophysical Analysis Letters.
