New geologic studies have recently validated the idea that a megathrust fault does run along the Queen Charlotte plate boundary. This complex and active fault has the capacity to release very large earthquakes and tsunamis. This fault, located near Haida Gwaii, is characterized by the Pacific tectonic plate subducting beneath the North American plate at a rate of 2.5 centimeters per year. This rate of movement even comes in near the rate of human fingernails. Surprisingly, it demonstrates the dynamic state of this wonderfully unique geological province.
The Queen Charlotte plate boundary is unique in having produced Canada’s two largest recorded earthquakes. The most significant event occurred on August 21, 1949, when an 8.1-magnitude earthquake impacted British Columbia’s Central Coast at precisely 8:01 p.m. The rattlings were felt up to 200 kilometers away in Prince Rupert, where glass broke and structures shook. For people on Haida Gwaii, the shaking was off the Richter scale. It made chimneys fall and even knocked cows off their legs!
In 2015, a twin 7.8-magnitude earthquake struck the same region. It released a tsunami, which underscored the grave hazards associated with this fault line. This 2008 earthquake reinforced the idea that the Queen Charlotte plate boundary is an early-stage subduction zone. As researchers point out, this new subduction zone is a work in progress. It no longer features one of the key ingredients found in well-established subduction zones, such as areas of elevated small earthquake activity and volcanic arcs.
There are huge implications of these findings—not only for researchers, but for planners, as well. Kelin Wang, a research scientist at the Geological Survey of Canada, emphasized the importance of this study. It still provides important verification of the megathrust fault. The high-resolution imaging of these underwater geological features presents compelling evidence of suitability. This subduction zone almost certainly produces large megathrust earthquakes and tsunamis.
This lesson comes from Michael Bostok, a professor at the University of British Columbia. Most importantly, he stressed that the new images captured through this research show more than ever the potential for very big, damaging seismic activity in the future. He stated that understanding these geological features is crucial for developing better tsunami models that can help mitigate risks associated with large seismic events.
The Cascadia subduction zone, just offshore from Vancouver Island, is accumulating stress at a remarkable four centimeters per year. That’s even quicker than the jolt experienced during the last major quake along a similar tectonic fault line at the Queen Charlotte fault line! This contrast serves as a reminder of the decidedly non-uniform nature of tectonic activity throughout the provinces of British Columbia.
The continuing research on the Queen Charlotte plate boundary will greatly benefit our scientific communities. It will better equip underserved communities, who are at increased risk, with emergency preparedness and response strategies. This is precisely why scientists actively monitor seismic activity in this area. They work hard to provide timely, relevant data that will assist in long-range planning and infrastructure improvements.
