Volcanoes

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Stacks of lava that are very thick can take years to cool down completely. Lava forms a thin crust at the top that cools in 10 to 15 minutes, but the flow underneath can take much longer to cool.

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  • What is the most destructive volcano in the world?

    Q: What is the most destructive volcano in the world?

    A: To humans, the most destructive volcano in the world is Mount Tambora in Indonesia. This volcano created the most powerful eruption in known history and killed 100,000 people along the way. Its eruption was 100 times more powerful than Vesuvius.
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  • What is a mudflow on a volcano called?

    Q: What is a mudflow on a volcano called?

    A: Mudflow on a volcano is called lahar and is typically caused by heavy rains during or after volcanic eruptions. Lahars can also occur when nearby ice or snow melts, carrying ash and rock debris down a volcano's slopes.
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  • Why are there volcanoes?

    Q: Why are there volcanoes?

    A: Volcanic vents allow the Earth to release built up gases from the heat and pressure emanating from its core. Magma rises towards the surface, and as the pressure builds the magma seeks outlets through which to flow. The higher the pressure build-up, the greater the volcanic explosion.
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  • What are the main features of a volcano?

    Q: What are the main features of a volcano?

    A: The main features of a volcano include a vent, a summit crater and a magma chamber. The vent is an opening through which volcanic material is erupted. Volcanoes can have more than one vent. The summit crater is the large concave opening that holds the central vent at the top of the volcano. The magma chamber is the large pool-like structure inside the volcano that holds the magma.
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  • What is the oldest volcano in the world?

    Q: What is the oldest volcano in the world?

    A: Mt. Etna is considered the oldest volcano in the world. Its first recorded eruption took place around 1500 B.C.E. Since that date, the volcano is believed to have erupted an additional 190 times.
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  • When will Yellowstone erupt?

    Q: When will Yellowstone erupt?

    A: Predicting when the next eruption will occur is difficult; however, the National Science Foundation estimates the next major eruption shouldn't happen for at least another one million years. The next eruption may dump several inches of ash over a large portion of the United States and could change Earth's climate.
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  • What are the different parts of a volcano?

    Q: What are the different parts of a volcano?

    A: The main parts of a volcano include the summit crater, the magma chamber, the central vent and the edifice. While volcanoes vary considerably in terms of size and shape, most land volcanoes have structural similarities.
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  • What is a main vent in a volcano?

    Q: What is a main vent in a volcano?

    A: The main vent of a volcano is the outlet chamber in the Earth's crust that allows hot magma to reach the surface. While secondary vents may form to alleviate the pressure caused by a magma chamber, the main vent is responsible for giving volcanoes their familiar cone shape.
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  • What is the closest volcano to Denver, Colorado?

    Q: What is the closest volcano to Denver, Colorado?

    A: There are no active volcanoes near Denver, Colorado. Nearby extinct volcanoes are located 2 hours from Denver in the Central Colorado volcanic field. These include the Grizzly Peak and Mount Aetna cauldrons and Bonanza and Marshall Creek calderas. The Central Colorado Volcanic Field is located in Park and Teller counties.
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  • What causes a volcano to erupt?

    Q: What causes a volcano to erupt?

    A: A volcano erupts when the pressure of a subterranean pool of magma becomes great enough to crack the earth's crust. Whether the eruption results in a violent explosion or a slow seepage depends on several different factors, according to How Stuff Works.
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  • What do volcanologists do?

    Q: What do volcanologists do?

    A: Volcanologists study the processes of volcano formation and their eruptive activity. In addition to studying current volcanic activity, they also study the eruptions of volcanoes throughout history.
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  • How tall is Mount Vesuvius?

    Q: How tall is Mount Vesuvius?

    A: Mount Vesuvius is a volcano that is roughly 4,300 feet tall, according to About.com's Ancient/Classical History expert. It is located in Italy, near the Bay of Naples.
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  • How does a volcano form?

    Q: How does a volcano form?

    A: A volcano forms when a vent in the Earth's crust allows magma to well up from below. The magma fills a void underneath the surface, and when it builds up enough pressure, it bursts through to the surface. As the magma cools, it hardens into rock, and multiple eruptions may build up the mountainous form of a volcano.
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  • What is an active volcano?

    Q: What is an active volcano?

    A: An active volcano is one that has had at least one eruption in the past 10,000 years. An active volcano can be dormant or erupting.
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  • What causes volcanic eruptions?

    Q: What causes volcanic eruptions?

    A: Volcanic eruptions occur when magma builds up beneath the Earth's crust and forces its way to the surface. Natural vents in the crust allow magma passage to the surface, and eruptions occur when the magma that forms is less dense than the material above it, causing it to flow upward. In some cases, this flow is slow and steady, but it can also be rapid and violent.
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  • What is an ash cloud?

    Q: What is an ash cloud?

    A: An ash cloud is a large cloud of smoke and debris that forms over a volcano after it erupts. Ash clouds consist of several elements, including ash, gases, dust, steam, rock fragments and other materials that come from inside the volcano and combine in the air above the crater.
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  • When did Mount Saint Helens erupt?

    Q: When did Mount Saint Helens erupt?

    A: Mount St. Helens' most significant eruption in modern times occurred on March 20, 1980. It was followed by additional eruptions between Dec. 7, 1989 to Jan. 6, 1990, Nov. 5, 1990 to Feb. 14, 1991, Oct.11, 2004, Mar. 8, 2005, and between Jan. 16, 2008 to July 10, 2008.
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  • What is a magma chamber?

    Q: What is a magma chamber?

    A: A magma chamber is a structure made up of solidified crystal mush and molten rock located below the surface of the Earth. When a magma chamber solidifies and cools, it is known as a pluton.
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  • What country has the most volcanoes?

    Q: What country has the most volcanoes?

    A: Indonesia has the most volcanoes, with 76 volcanoes that have erupted within historical times. The Smithsonian Institution has 141 Indonesian entries in its volcano database; this includes volcanoes which have yet to erupt.
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  • What is the Pacific Ring of Fire?

    Q: What is the Pacific Ring of Fire?

    A: The Pacific Ring of Fire is the name for a horseshoe-shaped region of high seismic and volcanic activity surrounding the Pacific Ocean Basin. In addition to volcanoes, the area encompasses major fault zones. It spans 25,000 miles and touches a number of island chains, as well as four continents.
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  • How do volcanoes affect the environment?

    Q: How do volcanoes affect the environment?

    A: An erupting volcano emits gases and dust particles that can cause profound changes in weather and climate throughout the world. Volcanism also affects the environment by producing acid rain and making ocean water warmer.
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