Scientists used advanced hydrophone technology to image the Queen Charlotte fault, confirming its potential for destructive megathrust earthquakes.
New research on the Queen Charlotte fault system has produced the first images of its subsurface structure off the coast of Haida Gwaii, confirming that northern British Columbia is capable of generating megathrust earthquakes.
These types of earthquakes occur where one tectonic plate is forced beneath another—in this case, the Pacific plate being driven under the North American plate—and they are known for producing both intense shaking and tsunamis.
Advanced hydrophone technology
An international team of scientists from American and Canadian institutions, including Dalhousie University, collected the data using a 15-kilometre-long hydrophone streamer. This instrument, equipped with thousands of underwater microphones, was towed through the region to capture seismic signals and map the deep structure of Earth’s crust.
The findings, published in Science Advances, present the first definitive evidence that the Pacific plate is beginning to collide with and subduct beneath the North American plate in the Haida Gwaii area. In practical terms, this means the region has the potential to generate earthquakes capable of both strong ground shaking and destructive tsunamis.
In fact, the Queen Charlotte fault system represents the greatest seismic hazard in Canada, producing the country’s largest recorded earthquake in 1949.
“This region is actively becoming a subduction zone, so understanding the fault structure here tells us about the early stages of subduction zone development,” says lead author Collin Brandl, a postdoctoral research scientist at the Lamont-Doherty Earth Observatory, part of the Columbia Climate School.
“Our study provides the first direct observations of the Haida Gwaii thrust, the “megathrust” of this system, which can help improve hazard analysis in the region, better preparing residents for future earthquakes and tsunamis.”
Reference: “Seismic imaging reveals a strain-partitioned sliver and nascent megathrust at an incipient subduction zone in the northeast Pacific” by Collin C. Brandl, Lindsay L. Worthington, Emily C. Roland, Maureen A. L. Walton, Mladen R. Nedimović, Andrew C. Gase, Olumide Adedeji, Jose Castillo Castellanos, Benjamin J. Phrampus, Michael G. Bostock, Kelin Wang and Sarah Jaye Oliva, 18 July 2025, Science Advances.
DOI: 10.1126/sciadv.adt3003
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