An international team of researchers has unearthed a 72-kilometer fault line hidden beneath the Saanich Peninsula on Vancouver Island, Canada. This discovery sheds light on the region’s seismic history and carries implications for future earthquake and tsunami risks.
Earth scientists have long suspected seismic activity in the Georgia Basin, but dense forest cover made evidence difficult to find. This research team, however, combined historical imagery analysis, remote sensing, and field surveys to uncover the fault line’s secrets.
Their key discovery came through trench digging, which revealed mineral patterns indicative of past rock fractures and movements, confirming the presence of a fault line. Further study revealed its length of approximately 72 kilometers.
The XEOLXELEK-Elk Lake Fault, as the researchers named it, is unique in its “slip-dip” nature, where rock blocks move vertically instead of sideways. This fault runs diagonally across the Saanich Peninsula, north of Victoria.
A potentially significant finding is the risk of a future earthquake generating a tsunami. The fault line’s proximity to the Saanich Inlet raises concerns for coastal communities in Canada, including Victoria and Vancouver, and in the U.S., including Seattle, Bellingham, Olympia, and Tacoma.
While predicting the timing of future earthquakes remains impossible, the researchers estimate the last earthquake on this fault occurred between 2,300 and 4,700 years ago, with a likely magnitude between 6.1 and 7.6.
This discovery highlights the importance of ongoing research in understanding seismic risks and preparing for potential natural disasters. By understanding the past, we can better prepare for the future.