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Why Does the Ring of Fire Exist?

The Pacific Ocean is encircled by narrow regions of frequent earthquakes and violent eruptions; this belt of seismic activity is often called the Pacific Ring of Fire. It has its origins in the motions of tectonic plates in the Earth's crust.

Function
- Earth's core has some heat left over from the planet's formation; it also derives heat from radioactive decay of unstable elements, so its temperature is believed to be as high as 12,000 degrees Fahrenheit, according to Scientific American. Liquid rock in the mantle heats up and rises, while cooler molten rock from beneath Earth's crust sinks; this pattern creates large convection currents in the mantle, causing the plates of solid rock that make up the crust to move slowly like large sheets of ice floating on a sea.
Features
- The boundaries of the Pacific Ocean feature a number of subduction zones where one tectonic plate is being forced beneath another. In these subduction zones, the leading edge of one plate will melt as it plunges into the mantle, causing volcanic eruptions as the molten rock rises and breaks through the crust. If one of the two plates becomes stuck temporarily, pressure may build up; eventually, the plate may move suddenly, causing an earthquake.
Considerations
- The Pacific Ocean and the adjacent regions are not one single plate; rather, there are multiple plates, including the Nazca Plate off the coast of South America, the Pacific Plate in the Central Pacific, the Indo-Australian Plate, the North American Plate, the Eurasian Plate, and the Philippine Sea Plate. Collisions between these plates -- and the subduction zones created by these collisions -- create the belt of seismic and volcanic activity called the Ring of Fire.

Nature