Scientists are increasingly concerned about the risk of a catastrophic earthquake and tsunami hitting the U.S. Pacific Northwest, with new studies predicting a 37% chance of such an event occurring in the Cascadia Subduction Zone (CSZ) by the year 2100. This fault line, nearly 700 miles long, stretches from northern Vancouver Island through Washington, Oregon, and Northern California, where the Juan de Fuca Plate is slowly sliding beneath the North American Plate. The CSZ’s last major seismic event occurred in 1700, and experts believe the region is overdue for another.

If a magnitude 8.0 to 9.0 earthquake strikes the CSZ, scientists warn that the coastline could drop by up to eight feet instantly, triggering a 100-foot tsunami. FEMA estimates that such a disaster would kill nearly 14,000 people and injure over 100,000. The economic fallout would exceed $134 billion, damaging over 618,000 structures—including more than 2,000 schools and 100 critical facilities. Rising sea levels caused by climate change could intensify the damage, with floodwaters pushing farther inland than previously estimated.

A Virginia Tech-led study suggests that the massive tsunami would permanently alter the geography of the region. As the land sinks and floodwaters recede, the footprint of 100-year floodplains in California, Oregon, and Washington could expand by up to 115 square miles, placing more homes, infrastructure, and roads in danger zones. In a worst-case scenario, this expansion could more than double due to land subsidence. Once changed, the land and flood risks could persist for centuries, reshaping how communities exist and rebuild.

The last major earthquake in the CSZ in 1700 generated tsunami waves that struck within 30 minutes, destroying coastal communities with no survivors reported. The geological stress in the CSZ has been building steadily, and experts believe the region is nearing another critical rupture point. The seismic tension between tectonic plates is not released smoothly, but rather stored and unleashed in violent quakes and tsunamis.

Scientists like Professor Tina Dura emphasize the urgency: when the next CSZ event occurs, it will unleash centuries of sea level rise within minutes. Preparedness, awareness, and infrastructure resilience are key to mitigating what could be one of the most devastating natural disasters in U.S. history.