A volcano is an opening in the earth's crust through which lava, volcanic ash, and gases escape. Volcanic eruptions are partly driven by pressure from dissolved gas, much as escaping gases force the cork out of a bottle of champagne.
What is a volcano? Volcanoes are openings, or vents where lava, tephra (small rocks), and steam erupt on to the Earth's surface. Many mountains form by folding, faulting, uplift, and erosion of the Earth's crust. Volcanic terrain, however, is built by the slow accumulation of erupted lava.
A volcano is a mountain or hill with an opening. When a volcano erupts, magma is pushed up through the opening with great force. When magma reaches the Earth's surface, it is called lava. Lava can be as hot as 2,200°F (1,204°C). Some volcanic eruptions are explosive.
Volcanoes are formed by eruptions of lava and ash when magma rises through cracks or weak-spots in the Earth's crust. A build up of pressure in the earth is released, by things such as a plate movement which forces molten rock to exploded into the air causing a volcanic eruption.
There are about 1,350 potentially active volcanoes worldwide, aside from the continuous belts of volcanoes on the ocean floor at spreading centers like the Mid-Atlantic Ridge. About 500 of those 1,350 volcanoes have erupted in historical time.
Sixty percent of all active volcanoes occur at the boundaries between tectonic plates. Most volcanoes are found along a belt, called the “Ring of Fire” that encircles the Pacific Ocean. Some volcanoes, like those that form the Hawaiian Islands, occur in the interior of plates at areas called “hot spots.”
Top 10 Facts About Volcanoes
Pacific Ocean
The Ring of Fire includes the Pacific coasts of South America, North America and Kamchatka, and some islands in the western Pacific Ocean.
Only 119 submarine volcanoes in Earth's oceans and seas are known to have erupted during the last 11,700 years. Hydrothermal vents, sites of abundant biological activity, are commonly found near submarine volcanoes.
What depth was the deepest recorded active volcano? – A team of researchers has documented a recent volcanic eruption on the Mariana back-arc in the western Pacific Ocean that is about 14,700 feet (4,500 meters), or 2.8 miles, below the ocean surface, making it the deepest known eruption on Earth.
A volcano is currently active if it is erupting lava, releasing gas or generating seismic activity. An active volcano is labelled dormant if it has not erupted for a long time but could erupt again in the future. When a volcano has been dormant for more than 10 000 years, it is considered extinct.
Computer models show why eruptive magma chambers tend to reside between six and 10 kilometers underground. A new study reveals why the magma chambers that feed recurrent and often explosive volcanic eruptions tend to reside in a very narrow depth range within the Earth's crust.
When lava first breaks through Earth's surface, it is an extremely hot liquid. On average, fresh lava can be between 1,300° F and 2,200° F (700° and 1,200° C)! Depending on its exact temperature, fresh lava usually glows either orange/red (cooler) or white (hotter).
While lava can be as hot as 2200 F, some flames can be much hotter, such as 3600 F or more, while a candle flame can be as low as 1800 F. Lava is hotter than a typical wood or coal-buring fire, but some flames, such as that of an acetylene torch, is hotter than lava.
Crater - Mouth of a volcano - surrounds a volcanic vent.
crater
At the top of the volcano, at its highest point, is a crater. Some volcanoes have something called a caldera.
Volcanoes can be of different shapes and sizes, but all contain some basic parts. The essential parts of a typical volcano are: 1) magma chamber, 2) lava, 3) primary vent, 4) throat, 5) conduit, 6) crater, 7) summit, 8) secondary vent, 9) secondary cone, 10) lava flow, and 11) ash cloud.
The main parts of a volcano include the magma chamber, conduits, vents, craters and slopes.
Volcanos - thesaurus
For starters, many people depend on volcanoes for their survival. The geothermal energy of a volcano can power technological systems for nearby communities. Soil near active volcanoes is often rich in mineral deposits and provides excellent farming opportunities.
Geologists generally group volcanoes into four main kinds--cinder cones, composite volcanoes, shield volcanoes, and lava domes.