A seamount sitting on a subducting tectonic plate off the coast of Japan and plowing its way into Earth's mantle may be at the root of several magnitude 7 earthquakes in the past 40 years.

Underwater volcano riding a sinking tectonic plate may have unleashed major earthquakes in Japan

Source: space
Source Link: https://www.space.com/underwater-volcano-sinking-tectonic-plate-japan-earthquakes