Two teams of geologists say portions of the seafloor along the Aleutian Islands in southwestern Alaska could produce tsunamis more devastating than anything seen in the past century. They say California and Hawaii are directly in the line of fire. Tsunamis — the giant waves generated by undersea earthquakes or landslides — have hit U.S. shorelines before. Often they start along the Aleutian island chain that curves in an arc across the North Pacific. Right underneath, there’s a trench where two pieces of the Earth’s crust are colliding. The edge of the Pacific Plate is shoving itself under the edge of the North American Plate.

Occasionally a segment of the trench along the plate margins gives way with ferocious results — a big earthquake. These subduction quakes are the type that produces a tsunami, as a giant section of the earth collapses. It’s like waving your hand underwater — the collapse creates a wave that can travel thousands of miles. In the past century, several such tsunamis have inundated parts of Hawaii, Alaska and California. FULL REPORT