Researchers in the Science Advances journal have found a "megathrust fault" that could ... long strip beneath North America ...

Tectonic drama at the Cascadia Subduction Zone – as it’s known to those who know – could generate two ferociously destructive things at once: a “megathrust earthquake” and a huge tsunami.

The Cascadia subduction zone, where the oceanic Juan de Fuca plate descends beneath the overlying North American plate, extends 1100 km from northern California to northern Vancouver Island.