Along the Pacific Northwest coast, scientists have long warned of a looming threat: a massive earthquake from the Cascadia Subduction Zone, capable of triggering tsunamis and devastating shaking. Now, new research highlights another, often-overlooked danger—the sudden sinking of the land itself and the longer-term threats posed by coastal flooding. A study authored by a team of scientists including USGS shows that a magnitude 8 or greater earthquake today along the Cascadia megathrust fault—stretching from northern California to Vancouver Island, British Columbia—could cause 0.5 to 2 meters (1.6 to 6.6 feet) of sudden land subsidence, instantly raising relative local sea levels and more than doubling the number of people, buildings, and roads exposed to coastal flooding.