A major geologic fault in Canada’s Yukon Territory has been found to be more active than previously thought, posing a significant earthquake threat in the future. Researchers from the University of Victoria have used high-resolution images and data to uncover evidence of “numerous large earthquakes” along the Tintina fault.
The 1,000 km-long fault was believed to be inactive for at least 40 million years, but new research suggests that it may experience additional seismic activity in the future. The team discovered a 130-km-long fault segment near Dawson City, which indicates seismic activity in the Quaternary Period.
According to Theron Finley, lead author of the study, small earthquakes along the Tintina fault have been detected in recent years, but these were not indicative of major ruptures. However, the expanding availability of high-resolution data has prompted re-examination of the fault for prehistoric earthquake evidence.
The research highlights a significant gap in Canada’s current understanding of earthquake frequency and risk, which is limited to the last couple of hundred years. The authors suggest that many active faults experience long periods between large ruptures, often thousands of years.
The study found glacial landforms that were laterally offset across a fault scrap by 1000 metres, indicating that the fault has slipped in multiple earthquakes throughout the Quaternary period. This suggests that the fault continues to accumulate strain at an average rate of 0.2 to 0.8 millimetres per year.
Future earthquakes on the Tintina fault could be major, exceeding magnitude 7.5, and potentially causing severe shaking in Dawson City. The region is also prone to landslides, which could be seismically triggered.
The research will be shared with local authorities, governments, and infrastructure planners to help mitigate risk. Earthquake frequency in Canada is common, with small earthquakes detected annually, but this study highlights the need for a more comprehensive understanding of seismic activity in the region.
Source: https://www.theweathernetwork.com/en/news/science/earth-science/science-ancient-fault-in-canada-could-produce-future-quakes-researchers-warn