Over the years, local evidence of the disaster has disappeared. But Douglas firs in Oregon may have caught hints deep in their tree rings. A night when January 1700 was about to end, two tectonic plates moving along the Pacific Northwest coast freed the tension they had piled up during a conversation lasting for centuries. An earthquake of roughly 9.0 magnitude clattered the whole region with the coastline dropping and tsunamis washed over the whole Northwest coast.