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

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 long-feared monster earthquake off the coast of California, Oregon and Washington could cause some areas to sink by more than 6 feet, dramatically heightening the risk of flooding.