Volcano Facts

Volcano Facts
  • A volcano is a mountain that opens downward toward a pool of molten rock, which is called magma. This all happens below the surface of the earth. So a volcano is essentially hole in the Earth from which molten rock and gas erupt.
  • The name “volcano” has its origin from the name of Vulcan, a god of fire in Roman mythology.
  • As pressure in the molten rock builds up it needs to escape somewhere. So it forces its way up through fissures, which are narrow cracks in the earths crust. Once the magma erupts through the earth’s surface it’s called lava.
  • Magma is liquid rock inside a volcano. Fresh lava ranges from 1,300° to 2,200° F (700° to 1,200° C) in temperature and glows red hot to white hot as it flows.
  • There are around 1,510 active volcanoes in the world. We currently know of more which are under the oceans. At any given time, there is an average of about 20 volcanoes that are erupting.
  • The Earth’s crust is made up of huge slabs called plates, which fit together like a jigsaw puzzle. These plates sometimes move. When two plates collide, one section slides on top of the other, the one beneath is pushed down. Magma is squeezed out.
  • Volcanoes are like giant safety valves that release the pressure that builds up inside the Earth.
  • Over half of the world’s volcanoes arise in a belt around the Pacific Ocean called the Ring of Fire.
  • The largest volcano (and mountain) in our Solar System is Olympus Mons on the planet Mars. The volcano is 17 miles (27 km) tall and over 320 miles (520 km) across.
  • Mauna Loa is one of the five volcanoes that form the island of Hawaii. It is 60 miles long and 30 miles wide, it makes up half of the entire island. Mauna Loa, and Kilauea are the only active volcanoes. Mount St. Helens, in the state of Washington, is one of more than 100 active or potentially active volcanoes in the continental United States, Alaska, and Hawaii. Only Indonesia and Japan have more.
  • Of the approximate 100 active volcanoes in the US the one most likely to erupt is Mount Rainier. Indonesia has the most active volcanoes in the world – about 160.
  • A volcano can be either active, dormant or extinct. An active volcano is classified as one that has erupted in the last 1,000 years and is likely to erupt again. A dormant volcano is one that has not erupted in the last 1,000 years and may erupt again some day. An extinct volcano is unlikely to erupt again.
  • Most volcanoes will form over many thousands of years. However, they can sometimes appear very quickly. A volcano called Paricutin appeared in a Mexican field in 1943 and grew to 60ft in a week. Within a year, Paricutin was 1,000 feet tall.
  • There might be as many as 10,000 volcanoes underneath the ocean. The most famous ocean volcano is Surtsey. Located off the coast of Iceland, it erupted in 1963 and formed a new island which is now home to thousands of seagulls and seals.
  • Nearly 5 million people live close to active volcanoes. One of the most famous volcanoes is Mount Vesuvius in Italy. Several million people live close to this dangerous, active volcano.
  • The 1883 eruption of the volcano Krakatoa killed roughly 36,000 people. It was one of the loudest sounds ever made and scientists say it had the strength of 15,000 nuclear bombs.
  • Both Hawaii and Iceland are volcanic islands and have black beaches. The sand on these islands is made from the hot lava when it cools down, creating a rock called basalt.
  • In volcanic areas, like Iceland, the heat from volcanoes is used to produce hot water and runs power plants. In Japan, it is common for people to bathe in warm volcanic sand. It is supposed to have healing qualities to cure illness and skin conditions.
  • Volcanic ash is very good for farmlands in surrounding areas. The nutrients present in volcanic ash help to make the land very fertile. The maleo bird actually incubates its eggs using the heat from the volcanic sand.