1,000-Foot Mega-Tsunami Threatens U.S. West Coast in Next 50 Years
Published on: 6/7/2025
A catastrophic 1,000-foot “mega-tsunami” could strike the U.S. within the next 50 years if a powerful earthquake hits the Cascadia Subduction Zone.
A new study from Virginia Tech indicates a 15% chance of a magnitude 8.0 or greater earthquake along this fault line stretching from Northern Vancouver Island to Cape Mendocino, California.
Such an earthquake could unleash a tsunami devastating the U.S. West Coast, including parts of Alaska and Hawaii. Cities like Seattle and Portland would be especially vulnerable, with coastal land potentially sinking by up to 6.5 feet.
The destruction would be swift and severe, happening within minutes leaving no time for adaptation or mitigation. Mega-tsunamis differ from ordinary tsunamis, reaching heights of hundreds — or even thousands — of feet, endangering millions of lives. While Alaska and Hawaii are further from the fault line, they remain at high risk due to their own seismic and volcanic activity.
The Cascadia Subduction Zone has not experienced a major quake since 1700, making another event statistically overdue. A disaster of this scale would dramatically expand coastal floodplains, delay recovery timelines, and have long-term effects on land use and infrastructure.