Volcanoes have been erupting on Earth for BILLIONS of years, and they’re still creating new landscapes today! Volcanoes can seem mysterious and scary, but people all over the world have learned to live in close proximity to active volcanoes. Today we answer questions you’ve sent us about how they form, how they erupt, what magma/lava is, and how volcanologists work to predict when they might erupt. Our guest is Freysteinn Sigmundsson, a volcanologist and professor at the University of Iceland.
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- Volcanoes have been around for at least 3.6 billion years! And the newest volcanoes are just a couple of years old, as new craters have formed in recent eruptions in Iceland and elsewhere.
- Most volcanoes form at the boundaries of Earth’s tectonic plates. Iceland, for example, sits on top of the Mid-Atlantic Ridge. Iceland is also a hotspot, meaning the underlying ground is warmer than the surface area above. There are about 130 volcanoes in Iceland, which are part of 30 different volcanic systems.
- Earth’s core is extremely hot, so hot that it melts rocks. The inside of a volcano is filled with magma (molten rock). A volcano erupts when more and more magma accumulates under the Earth’s surface, building pressure and eventually breaking through the top layer of the Earth’s surface.
- Once magma flows onto Earth’s surface, it is called lava. Lava is orange because it is so hot it emits thermal radiation, a form of light produced by very high temperatures. Once lava starts to cool, it hardens back into rock.
- People all over the world live close to volcanoes. Sometimes this means they need to evacuate quickly if a volcano appears close to erupting. And sometimes their homes and towns have been destroyed. It’s very very rare for people to die because of a volcano, but eruptions can be very disruptive.
- Living near volcanoes can also come with benefits! Some volcanic areas have very fertile soil, making it ideal for growing crops. And areas with a lot of volcanic activity are great places to harness geothermal energy. Iceland uses geothermal energy to power about 70% of the country.
- Many volcanoes stay dormant, or inactive, for hundreds or even thousands of years.
- Volcanic eruptions are not very predictable. Scientists monitor seismic and volcanic activity in an effort to understand when the next eruption might be.
