subduction

Longer seismic ruptures have been found only on subduction megathrusts deep underneath the ocean.

One involves a near-shore tsunami, such as a magnitude 9 earthquake along the Cascadia subduction zone, just off the coast of California’s North Coast, Oregon and Washington.

A 559-mile long fault line located off Japan’s Pacific coast characterized by its subduction, in which one tectonic plate is forced under another, the Nankai Trough has produced devastating earthquakes every 90 to 200 years.

Those are the findings of a new study that examined the repercussions of a massive earthquake on the Cascadia subduction zone, which stretches from Northern California up to Canada’s Vancouver Island.

A particularly chilling prospect for Northern California, as well as Oregon and Washington, would be a magnitude 9 earthquake along the Cascadia subduction zone off the coast.