Pacific Ring of Fire

The Pacific Ring of Fire is an arc around the Pacific Ocean where many volcanoes and earthquakes are formed. The area is also called the Pacific Rim, a term which refers to the coastal areas of the countries round the Pacific.
About three quarters of the world's dormant volcanos and active volcanos are here. The ring is 40,000km long, and there are 452 volcanoes.
About 90% of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire. The next most seismic region (5–6% of earthquakes and 17% of the world's largest earthquakes) is the Alpide belt, which extends from Java to Sumatra through the Himalayas, the Mediterranean, and out into the Atlantic. The Mid-Atlantic Ridge is the third most prominent earthquake belt. 
The Ring of Fire is a direct result of plate tectonics and the movement and collisions of crustal plates.