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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  • What Are Some Examples of Extinct Volcanoes?

    Q: What Are Some Examples of Extinct Volcanoes?

    A: Some examples of extinct volcanoes include Aconcagua in Argentina, Mount Kenya in Kenya, Mount Ashitaka in Japan and Mount Buninyong in Australia. Extinct volcanoes have been inactive for a long period of time and are considered unlikely to erupt again.
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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 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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  • 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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  • 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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  • 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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  • When Did Mount Rainier Last Erupt?

    Q: When Did Mount Rainier Last Erupt?

    A: Washington state's Mount Rainier last erupted between 1894 and 1895, according to Geology.com. Residents of nearby cities heard explosions coming from the volcano's summit. The last magmatic eruption the volcano experienced was over 1,000 years ago. Geologists believe that Mt. Rainier is due to erupt again in the near future.
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  • What Happened When Mount Etna Erupted?

    Q: What Happened When Mount Etna Erupted?

    A: Noxious fumes and tremendous amounts of ash and molten lava spewed from Mount Etna in 1669 and killed more than 20,000 Sicilians. Just prior to this eruption, an associated earthquake killed an additional 15,000 people.
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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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  • How Many Super Volcanoes Are There in the World?

    Q: How Many Super Volcanoes Are There in the World?

    A: The Earth has approximately 20 known supervolcanoes, according to James Morgan, who write for the BBC News. What constitutes a "supervolcano" is not clearly defined, so the term is avoided in the literature, but it is often used in reference to two distinct phenomena.
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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 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 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 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 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 Are Active and Inactive Volcanoes?

    Q: What Are Active and Inactive Volcanoes?

    A: Active volcanoes are those that have erupted recently or regularly erupt, and inactive volcanoes are those that have not erupted for a long time. The exact time distinction between active and inactive volcanoes differs between experts.
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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 Is an Extinct Volcano?

    Q: What Is an Extinct Volcano?

    A: An extinct volcano is one that has not erupted in at least 10,000 years and is not expected to erupt in the future, according to Oregon State University. There can be confusion between dormant and extinct volcanoes, but the difference between the two is that a dormant volcano may erupt even if it is in the distant future.
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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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  • 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 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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