A new study from Virginia Tech warns that large swaths of the Pacific Northwest, including Northern California, Oregon, and Washington, could face devastating flooding, landslides, and tsunamis in the coming years.
Published in the Proceedings of the National Academy of Sciences, the research highlights a double threat: a major earthquake in the Cascadia subduction zone (CSZ) combined with rising sea levels due to climate change. According to the study, this seismic combo could cause coastal land to sink by up to 6.5 feet, dramatically increasing the risk of flooding.
In real terms, that means the area of land at risk of flooding would jump from 35 square miles to 116 square miles. That’s an increase that could put more than 14,000 additional residents, 22,500 structures, and 777 miles of roads underwater if an earthquake were to strike today.
The Cascadia subduction zone, stretching from Northern California to Vancouver Island, is already known as one of the most volatile seismic regions in North America. Researchers warn there’s a 15% chance of an earthquake with a magnitude of 8.0 or greater occurring there within the next 50 years. When paired with climate-driven sea level rise, the results could be catastrophic.
The study’s authors also pointed out a critical flaw in current tsunami preparedness plans. Existing tsunami inundation maps don’t account for the amplification effect of rising sea levels, meaning future tsunamis could penetrate further inland than anticipated.
“These hazards are not just theoretical—they’re a wake-up call,” said the researchers. “Communities in these regions must prepare now to minimize damage and protect vital infrastructure and ecosystems.”
While the timing of the next big quake is uncertain, the researchers modeled scenarios for both a present-day event and one occurring in 2100. In either case, the stakes are high for the Pacific coastline.
