How magma behaves when it gets gassed up
How magma behaves when it gets gassed up Geologist Ben Andrews taking video on the volcano Santa MarĂ­a in Guatemala. (Smithsonian photo/gnuckx, public domain)
How magma behaves when it gets gassed up
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Lava is the most famous hazard of volcanoes. It is featured in movies. It used to describe lamps. It is also used to describe chocolate cakes and mobile phone cases. But lava is only part of the volcano story. 

Lava is what we call magma when it flows out of a volcano. Magma is molten - or melted - rock. You would not want to stand in lava. It can be as hot as 2,000 Fahrenheit. At a walking pace you could outrun the majority of lava flows. So, what’s so hazardous about a volcanic eruption?

Sometimes magma does not flow out of a volcano. Instead, it explodes. It is an exploding mixture of hot gas, magma, and rock. When it comes out, it is fast and unpredictable. 

In an explosive eruption, pieces of hardening magma and rock are spewed upward. They form a hot plume of gas. They range from the tiny particles that make up volcanic ash to chunks the size of cars. As the plume blows downwind, it drops materials like a hail storm. It litters the landscape with volcanic rocks. A pyroclastic flow of hot gases carrying the heavier material may pick up speed as it sweeps down from the volcano. As the flow mixes with the surrounding air, lighter ash may get lofted up in a cloud. It can travel as far as thousands of miles. 

The bigger chunks are an immediate hazard to people and wildlife around the volcano. But the cloud of ash takes a long-term toll that can be devastating. In 1980 Mount St. Helens in Washington state erupted. It produced a pyroclastic flow that scoured the landscape at speeds up to 600 miles per hour. It lofted ash that settled on 11 states over the next few days. 

In 2010 Iceland’s Eyjafjallajökull volcano erupted, sparking electrical storms. It had  an ash plume more than 5 miles high. It spread over Europe and grounded airline travel for days. 

Geologists who study volcanoes and called volcanologists. They are trying to better understand the behavior of these pyroclastic currents. It is dangerous to capture data directly from an explosive eruption. So volcanologists such as Smithsonian’s Dr. Ben Andrews have found ways to capture data from a distance and simulate flows in laboratories. Ben’s Eruption Simulator uses laser beams and talcum powder. He can observe how erupted materials get distributed upward and outward in different scenarios.  

Learn more about Ben’s volcano research in the "Smithsonian Science How" webcast. Watch How Volcanic Eruptions Send Materials Up and Out. Ben will take you on an explosive journey while answering questions. 

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What is magma?
Write your answers in the comments section below

  • 24ajtrom
    1/02/2018 - 10:40 a.m.

    Magma is molten, or melted, rock. In this article, I learned the following things: Magma can be as hot as 2,000 degrees Fahrenheit. Sometimes, instead of magma flowing out of a volcano, it explodes! Magma is a mixture of hot gas, magma, and rock when it explodes out of a volcano. This article provided lots of information for me to read.

  • 24mjstie
    1/02/2018 - 10:41 a.m.

    Manama is molted or melted rock. Manama flows out of volcanoes. Manama can be as hot as 2,000 freight. Lava is called Manama. Sometimes magma does not flow out of volcanoes.

  • 24msleon
    1/02/2018 - 10:48 a.m.

    Magma is hot fluid below or within the earth's crust from which lava is formed by cooling... I think so there's your answer. Magma is that. It is just hot fluid below the surface basically. Put that in your essays, kids.

  • 24lclabo
    1/02/2018 - 10:49 a.m.

    Magma is a hot fluid or semifluid material below or within the earth's crust from which lava and other rock is formed by cooling. Magma is a hot lava like substance. This article was very interesting!

    • 24msleon
      1/09/2018 - 10:28 a.m.

      yeah lols

  • 24aenagy
    1/02/2018 - 10:51 a.m.

    Magma is another name for lava, that has come out of a volcano.
    Magma can get up to 2,000 degrees ferenight. That is really hot.

  • 24prforr
    1/02/2018 - 10:53 a.m.

    Magma is molten or melted rock. This article was interesting because it was about volcanoes which can hurt people. Also because it's talking about how people study it and stuff like that. I like how it tells us what pyroclastic flow is.

  • 24kmjohn
    1/04/2018 - 10:19 a.m.


  • 24zdgill
    1/04/2018 - 10:30 a.m.

    Magma is melted rock. What comes out of the volcano is a mixture of hot gas, rock, and magma. Magma is one of the deadliest thing in the world. It kills the people in sec. Magma kills animals habitat. Magma can be good because it makes islands.

  • Dakotar-bru1
    1/08/2018 - 09:46 a.m.

    Magma is molten or melted rock. When the volcano gets pressurized underground the volcano erupts and spews magma everywhere except when it comes out it is considered lava.

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