Researchers gain clear picture of fault that threatens Pacific Northwest
A fault off the Pacific coast could devastate Washington, Oregon and Northern California with a major earthquake and tsunami. Researchers mapped it comprehensively for the first time.
A silent colossus lurks off the Pacific coast, threatening hundreds of miles of coastline with tsunamis and devastating earthquakes.
For decades, scientists have warned about the potential of the Cascadia Subduction Zone, a megathrust fault that runs offshore along the coast from northern Vancouver Island to Cape Mendocino, California. When the fault — or even a portion of it — next snaps, it will reshape life in Oregon, Washington and Northern California.
Of particular concern are signals of massive earthquakes in the region’s geologic history. Many researchers have chased clues of the last “big one”: an 8.7-magnitude earthquake in 1700. They’ve pieced together the event’s history using centuries-old records of tsunamis, Native American oral histories, physical evidence in ghost forests drowned by saltwater and limited maps of the fault.
But no one had mapped the fault structure comprehensively — until now. A study published Friday in the journal Science Advances describes data gathered during a 41-day research voyage in which a vessel trailed a miles-long cable along the fault to listen to the seafloor and piece together an image.
The team completed a detailed map of more than 550 miles of the subduction zone, down to the Oregon-California border.
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