New research shows that in minutes after the earthquake hits, coastal areas of California, Oregon and Washington could drop over 6 and a half feet in elevation.

When an earthquake rips along the Cascadia Subduction Zone fault, much of the U.S. west coast could shake violently for five minutes, and tsunami waves as tall as 100 feet could barrel toward shore.

A major earthquake waiting to strike the Cascadia Subduction Zone isn’t the only natural disaster looming in the Pacific Northwest, new research shows.