Nepedia
Back to Discover
Fluent Reader
🌍

Volcanic cone

earth science Maturity 11-13 Next article →

Volcanic cones are some of the simplest shapes in nature. They are built when pieces of rock and lava fly out of a volcanic vent. This material is called ejecta. As the ejecta falls, it piles up around the vent. This creates a cone shape with a central crater at the top.

Mayon Volcano as of March 2020
Mayon Volcano as of March 2020

Different types of cones form depending on the size and kind of fragments that erupt.

One type is the stratocone, which is also called a composite cone. These are large and have a very steep profile. They are made of many layers of lava flows and rocks. These rocks are called pyroclastic rocks, which means they were moved by explosions. Stratocones often have a central core of rocks that can be several kilometers wide. Some even have large, collapsed craters known as calderas.

Landscape osorno petrohue 2
Landscape osorno petrohue 2

Spatter cones are smaller hills that form near lava fountains. These fountains spray blobs of molten lava into the air. The blobs are called spatter. They do not have time to cool completely before they hit the ground. Because they are still soft, they stick together like taffy. This process is called welding. This builds a cone made of spatter that is welded together.

Puu Oo cropped
Puu Oo cropped

Tuff cones form when magma hits water or wet ground. This causes a phreatic explosion, which is an explosion driven by steam. These eruptions send out fine ash that feels like flour. The ash builds up into thick layers. Tuff cones have steep slopes and high rims. Tuff rings are a similar type but have much gentler slopes.

Koko Crater
Koko Crater

Diamond Head in Hawaii is a famous tuff cone.

Cinder cones are small, steep, and often very symmetrical. They are built from loose fragments like cinders or scoria. These bits are blown into the air by gas-charged lava. The fragments fall around the vent to make a bowl-shaped crater. Many cinder cones only erupt one time. Parícutin in Mexico is a famous example. It began erupting in a cornfield on February 20, 1943.

Paricutin
Paricutin

It erupted for nine years until 1952.

339 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (6)
File:Mayon Volcano as of March 2020.jpg
Mayon Volcano as of March 2020.jpg
File:Landscape osorno petrohue 2.jpg
Landscape osorno petrohue 2.jpg
File:Puu Oo cropped.jpg
Puu Oo cropped.jpg
File:Koko Crater.jpg
Koko Crater.jpg
File:Cinder cone volcano.jpg
Cinder cone volcano.jpg
File:Paricutin.jpg
Paricutin.jpg
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.