Scientists Warn of Major Earthquake Risk on U.S. West Coast

New research warns that a massive earthquake along the 700-mile-long Cascadia Subduction Zone could cause coastal land in the U.S. to sink by up to 6.5 feet within 30 minutes, especially if combined with rising sea levels from climate change.

The most at-risk areas include southern Washington, northern Oregon, and northern California. A quake of magnitude 8.0 or higher could more than triple the flood-prone area, exposing thousands of people, buildings, and miles of roads to greater flood risk.

The last big quake in this zone occurred in 1700, and such events typically happen every 400–600 years, suggesting the region is due for another.

By 2100, sea levels may rise up to 3 feet, making the impact even worse—potentially expanding the floodplain by 142 square miles, damaging infrastructure like airports, hospitals, schools, and contaminating farmland with saltwater, leading to major economic and environmental losses.

The study emphasizes that similar threats exist in other active subduction zones around the world and could inform global disaster planning.