In the remote Yukon Territory of Canada, a significant seismic threat is looming over Dawson City, home to about 1,600 residents. Recent research published in Geophysical Research Letters suggests that this serene town, along with others nearby, may soon experience a major earthquake. This looming danger comes from the Tintina fault, a massive geological line measuring about 620 miles that stretches northwest into Alaska. Although it’s remained mostly dormant for about 12,000 years, signs of awakening are starting to show.
According to Theron Finley, the leading author of the study and a recent graduate from the University of Victoria in Canada, while small earthquakes have occurred along the Tintina Fault over the past few decades, nothing has hinted at the possibility of significant ruptures. However, the reality that the geological record uncovers indicates a far greater threat. There’s much more to Tintina than we previously thought.
The focus for Finley and his team was on an 80-mile segment of the fault that runs close to Dawson City. Their research revealed surface features implying that several large earthquakes have struck the region throughout relatively recent geological times, notably during the Quaternary Period, which spans 2.6 million years to the present day. To deepen their understanding, the researchers utilized high-res images from planes, satellites, and drones—some captured using lidar technology—to analyze the fault with unprecedented detail, revealing geological surprises.
They stumbled upon a prominent fault scarp—essentially a sign where the land has shifted, indicating a 1,000-meter (3,280 ft) disruption that remains as a fingerprint of past seismic activity. This particular shift likely occurred approximately 2.6 million years ago. Down the fault at another location, they discovered a scarp showing a smaller misalignment of 75 meters (250 ft), attributed to a lesser quake around 132,000 years ago. Interestingly, there have been no notable significant earthquakes detected in the last 12,000 years, suggesting a long-term stability along Tintina during the Holocene Epoch.
For folks today living in Dawson and its surroundings, that seeming stability may not provide comfort. The absence of earthquakes doesn’t equate to inactivity. According to Finley and his experts, the fault is gradually in motion, accumulating strain at a rate between 0.2 mm and 0.8 mm each year. Those seemingly minor measurements can pile up over 12,000 years, leading to a potentially devastating release of energy when the fault finally lets loose.
Finley cautions, “We have assessed that future earthquakes along the Tintina fault could have magnitudes exceeding 7.5.” He added that their data suggest the fault may be nearing a perilous stage in its seismic cycle, having accumulated strain of about 6 meters (20 ft) over the last 12,000 years, setting the stage for a powerful quake.
A quake of this magnitude would impressively rival major historical quakes, such as the catastrophic 1976 Tangshan earthquake in China, which took potentially 240,000 to 650,000 lives. Comparatively, the sparsely populated Yukon would likely see far fewer casualties, but the potential for death and significant infrastructure damage remains high, applying even to roads, mines, and potential landslides triggered by seismic events.
The research team concluded, “Our findings carry notable implications for the seismic safety of the Yukon Territory and nearby Alaska. If it really has been 12,000 years since the last major quake, the fault is primed for an intense build-up of strain.” Ultimately, it remains a mystery when this mounting tension will be unleashed. Scientists can only alert residents of the persistent risks and encourage them to prepare themselves with emergency supplies and evacuation plans for what may come.
Correction, July 30: The story previously misidentified the year of the Haitian earthquake; it occurred in 2010, not 2020.
