SEATTLE – At the Seismology Lab at the University of Washington, there is concern that the 7.7 magnitude earthquake that occurred on the British Columbia coast over the weekend could affect Washington.
“Earthquakes trigger more earthquakes," said Washington State seismologist John Vidale, who has long studied how different fault zones in Southern California affect each other, and is looking at the potential for the same effects here.
“We need to watch the whole region with extra care,” said Vidale.
The earthquake caused virtually no damage to the sparsely settled group of islands known as Haida Gwaii, formerly named the Queen Charlottes. The quake did cause a small tsunami in Hawaii, but it was the sirens and the warnings that attracted the most attention.
But scientists who study these things say even though there were no collapsed buildings or boats washed inland, make no mistake, a magnitude 7.7 is a big earthquake, considered one of the most significant along the northwest coast in 60 years.
The quake was widely felt in British Columbia, and showed up on instruments in Washington.
Scientists also looked to see if the quake affected volcanos in Washington, and will remain on alert for at least several more weeks. So far, everything is quiet.
The problem, says Vidale, is that the West Coast, from Alaska to northern California, is under tremendous geologic pressure as it’s forced up against the basin that forms the Pacific Ocean.
Release the pressure in a major way along one fault, and it can then add to the pressure on another fault. As of early Monday afternoon, more than 130 aftershocks were recorded, including one more than 100 miles south of the quake’s epicenter, thought to be on the Cascadia Subduction zone.
The subduction zone threatens a much larger quake of approximately a magnitude 9 from the northern tip of Vancouver Island to Cape Mendicino California. The Haida Gwaii quake is not located along a subduction zone.