How magma behaves when it gets gassed up Geologist Ben Andrews taking video on the volcano Santa María 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, 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. When that exploding mixture of hot gas, magma, and rock 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. The 1980 eruption of Mount St. Helens in Washington state 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. 

The 2010 eruption of Iceland’s Eyjafjallajökull volcano sparked electrical storms. It had an ash plume more than 5 miles high, spreading over Europe and grounding airline travel for days. 

Geologists who study volcanoes - volcanologists - are trying to better understand the behavior of these pyroclastic currents. Given the danger of capturing data directly from an explosive eruption, 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 to 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 on Thursday, Dec. 14, 2017. Watch How Volcanic Eruptions Send Materials Up and Out, airing at 11 a.m. and 2 p.m. EST on the Q?rius website. Ben will take you on an explosive journey while answering your questions live. You can also get teaching resources to use with the webcast.

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


COMMENTS (121)
  • AlejandraC-del
    11/28/2017 - 08:27 p.m.

    This article is about lava. It gives you facts, details, and information. This includes information on as to what lava is, where it comes from, the effect it has, and different examples of it.

  • WilliamF-del
    11/28/2017 - 08:32 p.m.

    Volcanic Eruptions can be very dangerous. Magma can be outrun mast of the time however there are exceptions. When heavier material flow down they can increase speed also explode into flaming balls and cause major devastation.

  • SofiaT-del
    11/28/2017 - 08:37 p.m.

    This article mainly talks about lava and volcanoes. The article talks about eruptions and how deadly it could be if you are near by. Not only can these eruptions cause lava to hit, but it may cause other disasters; such as fires and electrical storms.

  • SarahT-del
    11/28/2017 - 09:12 p.m.

    This article is about how gas affects magma; a melted rock. When a normal eruption happened, hard manga and rocks are sent upward which make hot plumes of gas. The danger is that their size can reach up to the size of cars. Ashes are even worse; that could stretch over 11 states just like Mount St. Helen's eruption. Scientists are trying to figure out the kind of storms and the behavior of them using lasers to observe how erupted materials get disturbed upward or out.

  • NathalyP-del
    11/28/2017 - 09:24 p.m.

    The main idea of this article is about magma. Magma is in the lava which is another part of what makes lava, lava. Magma acts really off when it is gassed up.

  • JulianR-del
    11/28/2017 - 09:42 p.m.

    This article is about magma. Magma is featured in a lot of things, such as movies, and real life. Sometimes magma does not flow out of a volcano it explodes. Geologists who study volcanoes are called volcanologists.

  • EsmeraldaV-del
    11/28/2017 - 09:48 p.m.

    Magma is like lava, but when it flows out of a volcano. Magma is melted rock. If you've ever watched the movie Sharkboy and Lavagirl, you see in one scene that theres a volcano, and magma is flowing out of it!

  • AkshayB-del
    11/28/2017 - 10:35 p.m.

    This article is about how magma behaves when it gets gassed up. Magma is molten - or melted - rock. Sometimes magma does not flow out of a volcano. Instead, it explodes. When that exploding mixture of hot gas, magma, and rock comes out, it is fast and unpredictable. an explosive eruption, pieces of hardening magma and rock are spewed upward.

  • CherM-del
    11/28/2017 - 11:53 p.m.

    Lava is said and assumed to be the deadliest and worst thing about a volcanic eruption. However things such as iconoclastic flow, electrical storms,etc are the most dangerous to us. It can affect us by covering our land with ash,delaying airplane flights,etc. Lava is considered harmful and destructive, however our real threats are much bigger than that

  • GiannaC-del
    11/29/2017 - 01:16 a.m.

    We may think we know what lava is. But, what we don’t know is why can a volcano be so dangerous. Still magma can’t be that dangerous but a volcanic eruption can be very dangerous not just to people around it but to our entire earth’s environment. A volcanic eruption is very unpredictable behavior that when it happens it can cause lots of damage. The speeds and sizes that lava reaches to when it explodes out are very fast and they can go up to be the size of cars. If that hits you you’re most likely dead. Also, the polluted fumes that it releases can go into the atmosphere with the clouds and travel to another part of the world and affect you even thought your not even near where it occurred.

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