An international study led by researchers at The University of New Mexico has revealed new insights into the earthquake risk posed by the Queen Charlotte fault system off the coast of northern British Columbia. This research confirms that the region is capable of generating significant megathrust earthquakes and tsunamis.
The findings, published on July 18 in Science Advances, provide evidence that the Pacific Plate is partially colliding with and subducting beneath the North American Plate in the Haida Gwaii region. This reveals a fault zone with potential for catastrophic seismic events.
The study was co-led by UNM Earth and Planetary Sciences Professor Lindsay Worthington and UNM Ph.D. graduate Collin Brandl, along with researchers from U.S. and Canadian institutions. They used a 15-kilometer hydrophone streamer equipped with thousands of underwater microphones to map the ocean floor’s deep structure.
“We use tools that are similar to a medical X-ray or sonogram to image the Earth up to 10-20 miles below the surface. I’m always astounded by the detail of the images and our ability to interpret individual fault zones,” said Worthington.
The Queen Charlotte fault system is Canada’s largest seismic hazard and was previously poorly understood despite being the site of a magnitude 8.1 earthquake in 1949.
“The Queen Charlotte fault can be considered the San Andreas of the north—it’s the same type of fault and just as active. Because of its offshore location, we can use these sea-based tools to zipper up and down its length, providing detailed regional imaging that is not often possible with structures onshore,” Worthington explained.
This study underscores cross-border scientific collaboration’s importance and advanced geophysical tools in improving earthquake preparedness and risk assessment. Data were collected during a marine research expedition funded by the U.S. National Science Foundation and Natural Resources Canada.
“This work was a very fruitful collaboration between US and Canada-based scientists and a good lesson in sharing resources and logistical contacts for a successful expedition,” concluded Worthington.
The research enhances understanding of this key tectonic boundary, offering vital information for emergency planning efforts along the Pacific Northwest coast.
