Cinder cones tend to erupt for one period of time and then go extinct. They end up being hill-sized rather than mountain-sized. (R. Bishop)

Cinder cones tend to erupt for one period of time and then go extinct. They end up being hill-sized rather than mountain-sized. (R. Bishop)

Shield volcanoes form a vast, gently curved mountain as thin lava spreads a great distance before cooling. (R. Bishop)

Shield volcanoes form a vast, gently curved mountain as thin lava spreads a great distance before cooling. (R. Bishop)

When people hear “volcano,” they usually imagine the shape of a composite, or stratovolcano. (R. Bishop)

When people hear “volcano,” they usually imagine the shape of a composite, or stratovolcano. (R. Bishop)

Top: Mexico’s Paricutin cinder cone. Left: Mayon is a composite volcano. Right: Iceland’s Skjaldbreidur—“broad shield.”

Top: Mexico’s Paricutin cinder cone. Left: Mayon is a composite volcano. Right: Iceland’s Skjaldbreidur—“broad shield.”

Mayon ejects the hot cloud of lava fragments, ash, and smoke that make composite volcanoes dangerous. (AP)

Mayon ejects the hot cloud of lava fragments, ash, and smoke that make composite volcanoes dangerous. (AP)

Volcano Shape Up

Posted: March 5, 2018

Volcanoes made news headlines again this year. Reports told of billowing clouds, spurting and flowing lava, and ash-covered villages. Most readers don’t know there are different types of volcanoes. Here are three:

Cinder Cone Volcano

Shape: Symmetrical cone (round and the same from all sides). Smallest type of volcano

Vent: Single opening

Danger: Low because they are usually extinct after a single period of erupting

How it forms: Eruptions spray melted rock into the air. As this magma cools, it turns into small cinders. Those cinders fall from the sky, build up around the opening, and spill evenly down the sides.


Shield Volcano

Shape: Tall and broad with a gentle slope forming the curve of a warrior’s shield

Size: Some of the largest volcanoes in the world, if you go by the area they cover

Vent: One main opening, but lava also rises out of side fissures (cracks)

Danger: Medium, because they are not explosive. Glowing lava is extremely hot but slows down as it flows farther and farther, giving people time to move.

How it forms: Runny lava flows and spreads for great distances, hardening as it cools. Then more lava flows. Layers of hardened lava build up.


Composite Volcano

Shape: Mostly symmetrical and tall, with a wide base and steep top. Some of the world’s most scenic mountains are composite volcanoes.

Vent: Single main vent with many smaller side vents

Danger: High. Composite volcanoes explosively throw gobs of lava into the sky. They also release billowing clouds of super hot gases and ash. These pyroclastic flows can be up to 1,800 degrees. They can move as fast as 450 miles per hour! They also create sudden, dangerous mudflows called lahars.

How it forms: Various layers build up: layers of ash, cinder, bombs (big chunks of rock and lava blasted into the air), and layers of cooled lava.


Did you know?

Volcanoes can also be found in three conditions:

Extinct: Will never again be active

Dormant: At rest many hundreds of years, but capable of erupting again at any time

Active: Spewing or extremely likely to start erupting lava and gases