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Volcanism Matters: The Condensed Science Behind Eruptions and Their Aftermath

According to the United States Geological Survey (USGS), there are roughly 1,500 active volcanoes worldwide, excluding the continuous belt of volcanoes along the seafloor. A majority of volcanoes occur at or near tectonic plate boundaries. Of the volcanoes above water, a majority occur around the Pacific Ocean on a geological path known as the Pacific Ring of Fire, an area which made recent international news describing an explosion at the active volcano, Agung, in Bali, Indonesia. You can see a weekly report of Agung’s activity, along with its history, here.  

Nationally, the USGS monitors and reports on the 169 potentially active volcanoes in the U.S. Click here to see a map.  In the summer of 2018, the Kilauea Volcano in Hawaii erupted, causing massive evacuations, airline service disruptions and the destruction of property. The Hawaiian Volcano Observatory posts a weekly report on Kilauea that you can read here.

How do volcanoes erupt? What are some of the effects of those eruptions? Most of us have fond memories of elementary school science projects, especially memories of making a model volcano. Who can forget the mess made by wrapping clay around a container painted to look like a volcano? The best part was making it erupt, by mixing vinegar, baking soda and possibly red food coloring! This was always exciting to watch, however it is not how real volcanoes erupt, which is why it is called a model.

The baking soda and vinegar reaction is a chemical reaction; meaning the two reactants combine to produce a new product and during the process, energy is either given off or absorbed. A real volcano eruption is a physical reaction. A physical reaction is a change in the physical properties, rather than the chemical composition, of a substance. Ice provides a very basic example of a physical reaction. If you add heat to ice, it melts into liquid water, and if heated more, it evaporates into water vapor.

The Earth’s core is extremely hot, estimated between 5,000-7,000 degrees Celsius. This heat causes Earth’s mantle to warm and become less dense. Below the surface, the molten material is called magma. If the magma—which is composed of molten rock, dissolved gases and some various crystals—is less dense than the surrounding rocks, it can rise toward the Earth’s surface fueled by pressure from the dissolved gases. If the magma finds a weak spot in the Earth’s crust, it can cause an eruption. Once it reaches the surface, it is called lava.

When an eruption occurs, the magma cools into crystals and a variety of igneous rocks and the dissolved gases escape into the atmosphere. Due to the ash and dissolved gases escaping into the atmosphere, a large enough eruption can potentially impact global climate by blocking sunlight from reaching the Earth. According to the USGS, in the past, large and/or sustained eruptions have lowered the average global temperature by up to 0.5 degrees Fahrenheit. These same particles in the air can cause health concerns, if inhaled, and a disruption for air travel. However, as Volcano World has reported, volcanoes can also benefit the environment as well. The ash that settles on land can provide minerals that are beneficial to plant life. The heat from volcanic systems can be used as a source of geothermal energy. Lastly, mineral deposits such as copper, gold, and other metallic minerals can be found within volcanic regions. Check out Volcano World’s list of pros and cons here.

To learn more about volcanoes, geothermal energy and minerals, come by the Trever Reese-Jones Dynamic Earth Hall, Tom Hunt Energy Hall, and the Lyda Hill Gems and Minerals Hall. Learn more about different types of volcanoes here.

Links/Resources used and for more information:

U.S. Geological Survey. (2018, October, 29). What is a Volcano?. Retrieved from https://volcanoes.usgs.gov/vhp/about_volcanoes.html
U.S. Geological Survey. (2018, January 18). Volcanoes can affect the earth’s climate. Retrieved from https://volcanoes.usgs.gov/vhp/gas_climate.html
What are some good things that volcanoes do? Retrieved May 31, 2019, from http://volcano.oregonstate.edu/what-are-some-good-things-volcanoes-do

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