Volcanoes are cracks in the earth's crust where magma can flow to
the surface and turn to lava. A volcano is basically an outlet for
magma.
Volcanology is the study of volcanoes. Volcanologists are
scientists who study volcanoes. They must learn chemistry, geology,
physics, and earth sciences in school. They study volcanoes and how they
work throughout their careers. They also monitor and study volcanoes
and help determine if they'll erupt so people's lives can be saved if
there is an eruption.
Volcano scientists are like any other scientist and they like to classify their magma outlets. The first breakdown is the activity level of the volcano. They can be can be active, dormant, or extinct.
2. Dormants have erupted in our recorded history, but are quiet now.
3. Extincts haven't erupted in our recorded history and aren't expected to erupt in the future.
Scientists also classify volcanoes into different types.
1. Fissure volcanoes can form where tectonic plates are spreading apart, or at hot spots. Iceland is an island that is forming between the North American Plate and the Eurasian Plate.
2. Cinder cones are small hills of cooled lava. Most erupt only once. Cinder cones can form on other volcanoes.
3. Composites have lava flows and cinder rocks. (Composites are also called stratovolcanoes.) Composite volcanoes have layers of cooled lava and layers of hardened rocks and volcanic ash. These volcanoes usually explode because gasses build up, and they are common in subduction zones, when two plates converge and one goes under the other. The crater, or caldera, is bowl like at the top of a stratovolcano. Stratovolcanoes have many layers. Some layers are hardened ash, others are cooled lava, and others are hardened debris. Can release gasses, tephra, or rock fragments, and lava.
4. Lava domes can be explosive. Lava doesn't flow far from the vent. Can form within the crater of a volcano. Lava can plug the vent and then build up underneath.
5. Shield volcanoes have gentle slopes. Lava builds up in many layers, and the shield forms over a long time. They are built almost entirely of fluid lava flows. These are the least explosive volcanoes.
The Pacific Ocean sports a "Ring of Fire"
The pacific plate meets other plates forming a "ring of fire." There are over 400 volcanoes in the ring of fire. Some estimates say that 75% of all volcanoes lie in the ring of fire.
Creators and destroyers
Volcanoes can destroy land and change an area's climate. Volcanoes can also create land, as in the case of the Hawaiian islands, which were created by a volcanic hotspot. Whether creating or destroying, volcanoes can be exciting, explosive, and dangerous.
Gwen Nicodemus is a freelance engineer/writer and a homeschooling mom.