Ring of fire
The ring of fire is the linear chain of volcanoes, or volcanic arc, surrounding the Pacific ocean. Nine tenths of the world's volcanoes are concentrated there. This zone is also subject to many earthquakes.
On the American continent, it is formed from Andes cordillera, the Central American cordillera, the Cascade Range in the United States and the volcanoes of Alaska. It is found along the Aleutian Islands, and the islands of Japan and Indonesia. It passes around Australia in a wide curve including the Fiji islands and New Zealand.
This intense seismic activity takes place in subduction zones, where an oceanic plate is sliding under another continental or oceanic plate. On the American coast, for example, the continent is shifting roughly westwards. In the south Pacific, the Nazca plate is sinking eastwards under South America, lifting the Andes Cordillera. On the other side is the great Pacific plate that is sliding under Japan (remember that we are talking about plate movements relative to each other).
There are other volcanic arcs on Earth such as those of the Lesser Antilles, in the Atlantic and surrounding the Mediterranean.