Volcanoes

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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  • 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 damage do volcanoes cause?

    Q: What damage do volcanoes cause?

    A: Volcanoes cause physical damage to structures and buildings, wildlife, local vegetation and the atmosphere, as well as posing health risks. Residences within the vicinity of a volcanic eruption often receive timely notice before an eruption occurs. This reduces the likelihood of danger to humans.
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  • Where is Mount Kilimanjaro located?

    Q: Where is Mount Kilimanjaro located?

    A: Mount Kilimanjaro is located in Tanzania. It is a dormant volcano comprising three volcanic cones, and is the highest peak in Africa.
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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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  • 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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  • Are volcanoes mountains?

    Q: Are volcanoes mountains?

    A: While many volcanoes are mountains, it is possible for a volcano to erupt from a vent in any type of land form. Over time, volcanoes become mountains by depositing their discharge around them in ever-increasing layers. Not all mountains are volcanoes.
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  • Can lava melt concrete?

    Q: Can lava melt concrete?

    A: Concrete is a composite material, so it has no single melting point of its own. Each of the different components of concrete, primarily sand, gravel and cement, has a melting point of its own. Rather than melt concrete, molten lava causes it to rapidly decompose.
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  • What country has the most active volcanoes?

    Q: What country has the most active volcanoes?

    A: Indonesia has 147 volcanoes, 76 of which are still active making it the world's most active volcano country. The country consists of a chain of more than 13,000 islands that are spread out over an area similar in size to the continental United States.
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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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  • What are the positive and negative effects of volcanoes?

    Q: What are the positive and negative effects of volcanoes?

    A: The negative effects of volcanoes include the destruction of man-made and natural environments and the death of human, animal and plant life. On the other hand, volcanoes generate geothermal energy and produce nutrients that result in fertile soil.
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  • How was Mount Kilimanjaro formed?

    Q: How was Mount Kilimanjaro formed?

    A: Mount Kilimanjaro is a stratovolcano that formed as the plates below it dropped and porous basalt rock magma erupted through the surface of the ocean. The magma and other debris formed layers with each eruption, eventually rising high enough to bring Mount Kilimanjaro to its height of 19,341 feet.
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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 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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  • How often does Old Faithful erupt?

    Q: How often does Old Faithful erupt?

    A: Old Faithful erupts at varying intervals from 60 to 110 minutes in length. The Yellowstone National Park staff offers predictions based on past activity; this is so that visitors can plan a visit to the geyser area during an eruption, which lasts between one-and-a-half minutes and five minutes.
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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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  • What is a lateral blast?

    Q: What is a lateral blast?

    A: A lateral blast, also known as a lateral eruption, is a volcanic eruption that occurs out of the side of a volcano instead of at its summit. An example of a lateral blast is the 1980 eruption of Mount St. Helens.
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  • What gases are produced by volcanic eruptions?

    Q: What gases are produced by volcanic eruptions?

    A: Volcanic eruptions mainly produce steam (H2 0 ), sulfur dioxide (SO 2 ) and carbon dioxide (CO 2 ). They do release other gases in lesser amounts, such as carbon monoxide (CO), helium (He), hydrogen (H 2 ), hydrogen chloride (HCL), hydrogen fluoride (HF) and hydrogen sulfide (H 2 S).
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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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  • 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 conditions make for a violent volcanic eruption?

    Q: What conditions make for a violent volcanic eruption?

    A: According to the Oregon State University Department of Geosciences, a volcanic eruption may become violent if pressure builds up inside the volcano for any reason. An explosive eruption is much more dangerous than a steady flow of magma and can spread ash and pyroclastic material over a wide area. The eruption of Mount Saint Helens in 1980 was a textbook example of a violent, explosive volcanic eruption.
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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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