4.8 Volcanoes Lesson

There are hundreds of volcanoes all over the world. Over half are along the shores of the Pacific Ocean in a region called the Ring of Fire. Another large group of volcanoes are found under the Atlantic Ocean in the Mid-Atlantic Ridge. It is the largest mountain range in the world.

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​Where are volcanoes?

​This is a dormant volcano: a volcano that hasn't erupted recently, but it is expected to erupt again.

​This is an extinct volcano: a volcano that will likely not erupt again.

This is an active volcano: a volcano that is:

• currently erupting

• showing signs of erupting

• has erucpted recently
  

​Types of eruptions

​Mt. Saint Hellens had a huge pyroclastic flow that killed many people, animals and trees.

​Pyroclastic flow material passed over the moving avalanche and spread outward, devastating a fan-shaped area 37 km × 31 km In total, about 600 km² of forest were knocked down, and extreme heat killed trees miles beyond the blow-down zone.

​On Earth there are about 1500 active volcanoes.
450 of these are around the Pacific Ring of Fire.

​Kilauea is one of the world's most active volcanoes and has been erupting continuously since 1983.

​The Yellowstone Caldera, sometimes referred to as the Yellowstone Supervolcano, is a volcanic caldera and supervolcano in Yellowstone National Park in the Western United States. The caldera and most of the park are located in the northwest corner of Wyoming. The caldera measures 70 by 45 kilometers.

​The yellowstone Supervolcanoe provides the heat that makes all of the geysers and hot springs in the park.

​Volcanoes:
A Review of what we learned