The 350 children at Ocean Shores Elementary School have practiced their earthquake survival plans, dropping under desks to ride out the convulsions, then racing upstairs to the second floor to await the coming tsunami.

Unless something changes, their preparations will most likely be futile.

The Cascadia fault off the Pacific Northwest coast is poised for a massive 9.0 magnitude earthquake at some point, scientists say, a rupture that would propel a wall of water across much of the Northwest coast within minutes. Low-lying coastal neighborhoods in Washington, Oregon and Northern California would be under 3 meters or more of water, with the elementary school in Ocean Shores facing an inundation that could be 7 meters deep.