When the Cascadia fault line ruptures, it could be North America’s worst natural disaster in recorded history.
When the next very big earthquake hits, the northwest edge of the continent, from California to Canada and the continental shelf to the Cascades, will drop by as much as six feet and rebound thirty to a hundred feet to the west—losing, within minutes, all the elevation and compression it has gained over centuries.
Source: The Earthquake That Will Devastate the Pacific Northwest