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13 Parts of a Volcano: The Anatomy of Volcanoes

Volcano Anatomy

Parts of a Volcano

Volcanoes are often considered as one of the most destructive forces on Earth.

But do you know the anatomy of a volcano?

From tephra to volcanic bombs, it’s time to explore the 13 parts of a volcano.

Let’s dive right in.

1. Magma

When rocks become so hot, they can become a substance called magma. It collects in magma chambers on average 1 to 10 km below the surface.

2. Vent

Magma is lighter than the solid rock around it, so it rises. Eventually, some of the magma pushes through vents creating a volcanic eruption.

3. Lava Flow

Magma that erupts is called lava. If magma is thin and runny, gases can escape easily from it. When this type of magma erupts, lava flows outside the volcano. Lava flows are the molten rock that oozes onto the Earth’s surface after a volcano eruption.

4. Volcanic Bombs

These molten rocks are thrown out from a volcano and are at least 66mm in size. On exit, they cool down and become extrusive igneous rocks.

5. Lava Dome

When lava is too thick and sticky, it piles up around the vent and forms a dome. These circular mounds protrude from volcanoes because of the slow release of viscous lava.

6. Eruption Column

These clouds of heated ash and tephra are released from a vent during an explosive volcanic eruption. Within an eruption column and cloud, highly charged particles can generate thunder and lightning.

7. Eruption Cloud

Ash falls back down like powdery snow. But it’s snow that won’t melt. These blankets of ash suffocate plants and animals. The eruption cloud can extend up to 12 miles above a volcano. Then, it can reach thousands of kilometers in distance raining ash over regions.

8. Tephra

If magma is thick and sticky, gases cannot escape easily. Pressure builds up until the gases escape violently and explode. This type of eruption magma blasts up into the air and breaks apart into pieces called tephra. Tephra can range in size from tiny particles of ash to house-size boulders. Tephra destroys everything in its path.

9. Acid Rain

When sulfur dioxide and nitrogen oxide emitted from volcanoes reacts with water molecules in the air, it produces acid rain.

10. Pyroclastic Flow

This type of deadly flow contains fast-moving volcanic matter and hot gas. Pyroclastic flow moves away from a volcano and incorporates tephra. When lava domes collapse, it can create hot pyroclastic density currents.

11. Lahar

When hot volcanic material mixes with water from streams or snow and ice, lahar mudflows form. Mudflows can bury entire communities like Mount St. Helens in the 1980s. The positive outcome is that volcanic material breaks down and weather to form some of the most fertile soils.

12. Fumaroles

Holes, cracks, or fissures are on the surface near volcanoes. They emit steam and volcanic gases, such as sulfur dioxide and carbon dioxide. Fumaroles create pathways for rising heat, volcanic gas, and magma.

13. Crack

Openings stemming down into the pool of magma. Cracks and fumaroles act like a window so scientists can get a glimpse of the gases inside volcanoes.

13 Parts of a Volcano: The Anatomy of Volcanoes

Volcanoes are one of the most fascinating geological phenomena on earth. The beauty, power, and mystery behind these natural phenomena make them a source of fascination and awe that we never tire of watching.

Online courses are offered by universities around the world for those interested in learning more about volcanoes. Here are some options to check out to get increase your insights on volcanoes.

Alternatively, you can use the comment form below or email us with your questions and comments about volcanoes.


  1. When does it stop? How much magma is under us? Why does it force its way out? How does the magma find a volcano to break out with explosive force? In Palma Island, can the mountain side collapse and cause a great tsunami? Is that what is expected? What are scientists measuring?

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