Whitehorse, YT – Scientists are analyzing new samples from the Tintina fault near Dawson City to better understand the region’s earthquake risk, building on research that revealed the fault could still produce quakes up to magnitude 7.5.
Theron Finley, a surficial geologist with the Yukon Geological Survey, says the team collected sediment samples from a trench near the Dempster Highway to date prehistoric earthquakes.
By determining when past large quakes occurred, researchers hope to estimate how frequently the fault produces major ruptures.
“We were able to estimate an average slip rate over time, or an average rate at which the fault is thought to accumulate strain, but we weren’t able to say how frequently that strain is released in large earthquakes,” said Finley. “That’s ultimately the goal of doing this paleo seismic trench.”
A study published in August, led by Finley during his PhD at the University of Victoria, used high-resolution satellites to identify a 130-kilometre-long fault line near Dawson City. That research confirmed multiple large earthquakes in the past and suggested the fault could still generate major quakes.
“We can sort of say with confidence that the fault should still be treated as an active fault,” said Finley. “What we weren’t able to do in that initial work was to provide any information about the recurrence interval, so how frequently earthquakes happen.”
The new samples will be sent to specialized labs in the coming year to help fill that gap and improve seismic hazard assessments for the region.