The name "Ring of Fire" refers to a zone of frequent volcanic eruptions and earthquakes that encircles the basin of the Pacific Ocean. You could say that it's a ring of fiery volcanoes.
In the entire world, there are about 1,500 volcanoes that have been active within the last 10,000 years. About two-thirds of these volcanoes are located along the Ring of Fire.
To understand the Ring of Fire, you need to know a little about plate tectonics. Scientists believe that the earth's crust, or outer shell, is broken into about a dozen large plates and several smaller ones. These plates move relative to one another, although at a very slow rate about two to four inches a year. As they move, the plates interact with one another along their edges: they pull apart, or they grind past one another, or they slide over or under one another.
These interactions can produce volcanic eruptions. For example, when one plate slides under another plate, its edge gets pushed far down into the earth's interior. The high temperatures and pressure melts the rock, turning it into magma. Some of this magma rises to the earth's surface and erupts, creating chains of volcanoes.
The interactions between plates can also produce earthquakes. For example, imagine two plates that are gradually sliding past each other. At some points along their edges, the plates can get locked together, allowing pressure to build up. Ultimately, the pressure becomes great enough to fracture the rock at the locked point, and the built-up pressure is released as the plates' edges suddenly slide in opposite directions. This fracturing and release of pressure can result in a powerful earthquake.
Take a look at the Ring of Fire map on the website of the U.S. Geological Survey. Then compare this map to Rand McNally's Plate Tectonics Map. You'll see that the Ring of Fire always follows boundaries between plates. For example, the Asian section of the Ring runs along the Pacific Plate's boundaries with the Eurasian Plate and the Philippine Plate. Similarly, the South American section follows line along which the South American Plate meets the Nazca Plate and the Antarctic Plate.
In the United States, one of the most recent major events along the Ring of Fire was the eruption of Mt. Saint Helens on May 18, 1980. This volcanic mountain is located in southwestern Washington and is part of the Cascade Range. The violent eruption devastated a 230-square-mile area and killed 57 people.
Question submitted by a 7th-grade student at Corriher-Lipe Middle School in North Carolina.