Yukon fault thought long dormant could trigger 7.5 magnitude earthquake: new research

New research is sounding the alarm about a major geological fault in the Yukon capable of triggering earthquakes of 7.5 magnitude or more.

Known as the Tintina Fault , it has built up structural strain that could lead to a large quake within our lifetime, according to researchers at the University of Victoria. They published their findings earlier this month in the journal, Geophysical Research Letters. The UVic team was led by Ph.D student , Theron Finley.

The fault stretches about 1,000 kilometres from British Columbia to Alaska . It was once thought to be inactive for at least 40 million years — since before the last ice age ended. Now scientists say it has a history of large ruptures within the last 2.6 million years and could do so again.

An earthquake of 7.5 magnitude could damage the Klondike and Dempster highways, the researchers warn, potentially cutting off Dawson City and nearby communities from critical access routes. 

The Tintina Fault has not previously been recognized as a hazard within Canada’s National Seismic Hazard Model (NSHM), which informs earthquake building codes and engineering standards. However, despite its quiet surface, the researcher warn it is far from dormant.

Using high-resolution topographic data gathered by satellites, planes and drones, researchers discovered geological formations along the Tintina Fault, one about 2.6 million years old and another roughly 132,000 years old. They have shifted sideways by approximately 1,000 metres and 75 metres.

While this suggests multiple past earthquakes, the exact timing and frequency are not known. Researchers cannot definitively state whether the fault is building pressure or predict when the next earthquake might occur.

“We don’t know exactly when these have occurred, so you can’t actually then make statements about recurrence periods,” Yukon’s Geoscience Research Manager, Jan Dettmer told the Yukon News.

He cautioned against making definitive predictions about future seismic events and emphasized the need for additional study to fully understand the fault’s earthquake potential.

Unlike more active fault lines across the country, the researchers say Tintina was overlooked because faults in the region move very slowly and there are few instruments to detect earthquakes.

“I expect this (research) will trigger many studies in the next few years to much better understand what’s going on there,” Dettmer said.

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.

These findings will be incorporated into future updates and shared with local governments to improve emergency planning.

• Mike Pemberton wins Yukon Liberal leadership race, will be territory's 11th premier
• America's 49th state shows support for Canada that Trump wants to make its 51st

Our website is the place for the latest breaking news, exclusive scoops, longreads and provocative commentary. Please bookmark nationalpost.com and sign up for our daily newsletter, Posted, here.