Why Do So Many Big Earthquakes Strike Japan?

Live Science ^ | 11/22/2016 | Denise Chow

[JimSEA]

A magnitude-6.9 earthquake struck yesterday off the coast of Fukushima, Japan, likely along the same fault that ruptured in 2011, unleashing a massive 9.0-magnitude temblor that triggered deadly tsunamis and caused widespread destruction. Over the course of its history, Japan has seen its share of shaking, but what makes this part of the world so susceptible to big earthquakes?

The answer has to do with Japan's location. The island nation lies along the so-called Pacific Ring of Fire, an imaginary horseshoe-shaped zone that follows the rim of the Pacific Ocean, where many of the world's earthquakes and volcanic eruptions occur. In fact, 81 percent of the world's largest earthquakes happen in this active belt, according to the U.S. Geological Survey (USGS). [Image Gallery: This Millennium's Destructive Earthquakes]

[Paleo Pete]

I had forgotten a lot of the details, I was sure there was more than one plate involved in Japan but couldn’t remember which ones.

Lots of activity there though, one of the most active spots in the world.

[Axenolith]

The west coast has far less compressional force on it, essentially just the east edge of the spreading centers of the Juan de fuca, Explorer and Gorda plates and the mostly subducted Nazca, all producing the fractional melting facilitating the cascade volcanoes. Of course it gets big earthquakes, but geologically speaking it’s the slacker side of the ring of fire.