Study Warns Cascadia Earthquake Could Sink Pacific Northwest Coast 6 Feet

A series of new studies warn that a major earthquake along the Cascadia Subduction Zone—from Northern California to British Columbia—could cause coastal land to sink by up to six feet nearly instantly, drastically reshaping the landscape and expanding flood risk zones. Such an event, which has a significant chance of occurring within the next 50 to 75 years, could trigger devastating tsunamis, destroy infrastructure, and double or triple the number of residents, structures, and roads exposed to flooding, especially when combined with ongoing climate-driven sea-level rise. Communities in southern Washington, northern Oregon, and northern California are particularly vulnerable, with towns near Willapa Bay and Grays Harbor at high risk. Historical precedents from past earthquakes show that this sudden land subsidence can permanently alter coastlines and force relocation of entire communities. Experts emphasize the urgent need for urban planning that accounts for both seismic risks and climate change to mitigate potential loss of life and property. The findings underscore that without proactive measures, the Pacific Northwest could face a disaster on the scale of historic global earthquakes and tsunamis.