This part of the US is at highest risk for a devastating tsunami [Video]

Editor’s Note: The CNN Original Series “Violent Earth with Liev Schreiber” explores the harrowing weather events, from hurricanes and tornadoes to wildfires, that are increasingly frequent in our changing climate. It airs on Sunday at 9pm ET/PT. 

A catastrophic earthquake and tsunami are inevitable for the coast of the Pacific Northwest, scientists say. Planning for that means imagining a disaster unlike anything that’s ever hit the modern United States.

“30 or 40 years ago, we didn’t even know that big earthquakes were possible in the Pacific Northwest,” said Diego Melgar, a seismologist at the University of Oregon.

Scientists now know the 700-mile fault called the Cascadia Subduction Zone, 100 miles off the coast of Northern California stretching north to Vancouver Island, could trigger a 9.0 magnitude earthquake followed by a tsunami, which is exactly what happened in …