Overview

• A Proceedings of the National Academy of Sciences study puts the odds of an 8.0–9.0 magnitude earthquake in the Cascadia Subduction Zone at 37 percent over the next 50 years and nearly certain by 2100.
• Researchers warn such a quake would trigger 100-foot tsunami waves within minutes and cause instant coastal subsidence of up to eight feet across Washington, Oregon, California and British Columbia.
• Climate projections of up to two feet of sea-level rise by 2100 would exacerbate subsidence effects, expanding 100-year floodplains more than threefold in key Pacific Northwest regions.
• Federal Emergency Management Agency estimates the next CSZ event could claim about 5,800 lives from shaking and another 8,000 from the resulting tsunami, with hundreds of thousands of buildings damaged or destroyed.
• Experts caution that, despite advances in fault mapping and early-warning systems, coastal defenses and evacuation plans remain inadequate and call for integrated seismic and climate resilience strategies.