The Earth's volcanoes erupt most often near the boundaries of the 16 tectonic plates that form the planet's outer crust. The vast majority of those plate boundaries are found along ocean floors. When plates collide, brush past one another or even spread apart, the result is an escape of the hotter layer of material that exists just under the plates. Although most volcano eruptions occur along plate boundaries, there also are interior areas called hot spots that are sometimes the site of volcanic activity.
More facts about volcanoes:
- Volcanic activity at sea can lead to the development of a tsunami. This powerful wave is created when plates slide over or under one another, then suddenly spring backward. As a result, the displaced water generates a wave that is capable of traveling a great distance, engulfing coastlines and causing much damage.
- The most famous volcano in the world is Mount Vesuvius, which is located in the Bay of Naples in the southern section of Italy. The volcano has erupted at least 30 times since record-keeping began. One of the more notable eruptions occurred in 79 A.D., when an eruption of ash and lava covered the cities of Pompeii and Stabiae.
- The highest concentration of volcanoes is found in the South Pacific. With 1,133 volcanic cones and sea mounts spread over an area roughly the size of New York state, the possibility of an eruption is ever present.
