Categories: Astronomy

Volcano Crater

[/caption]
Some craters are formed by a meteor impact, when a space rock strikes the Earth. And other craters are volcanic in origin. A volcano crater is a circular depression around a volcanic vent. This is where the lava, ash and rock erupt out of a volcano. In most situations, the volcano crater is located at the top of the volcano.

Think of a classic cone-shaped volcano, with steep sides and a slightly flattened top. If you could climb up to the top of the volcano and peer over the edge, you would look down into the volcano crater. And when the volcano does erupt, the material comes out of this volcano crater.

But not all volcano craters are found at the top of the volcano. They can also appear on the flanks of large volcanoes, when side vents reach the surface and erupt. These are known as flank craters, while the crater on top is called a summit crater. The volcano crater will often fill up with water and create a crater lake.

One kind of eruption creates a crater without a volcanic cinder cone at all: a phreatic eruption. This is a situation where magma rises through water-saturated rocks and causes steam to build up under the surface. The pressure from all the steam causes the rock to explode outward and create a volcanic crater. These can be strange to discover as they often appear in plains, far away from any other obvious volcanoes.

When the ground depresses down because a volcano’s magma chamber has been emptied, this is actually known as a caldera, and not a volcano crater.

We have written many articles about volcanoes for Universe Today. Here’s an article about types of volcanoes, and here’s an article about cinder cone volcanoes.

Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.

We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.

Fraser Cain

Fraser Cain is the publisher of Universe Today. He's also the co-host of Astronomy Cast with Dr. Pamela Gay. Here's a link to my Mastodon account.

Recent Posts

Astronomers Find a 3 Million Year Old Planet

Astronomers have just found one of the youngest planets ever. At only 3 million years…

18 minutes ago

There was Hot Water on Mars 4.45 Billion Years Ago

Mars formed 4.5 billion years ago, roughly the same time as the Earth. We know…

4 hours ago

Axion Dark Matter May Make Spacetime Ring

Dark matter made out of axions may have the power to make space-time ring like…

8 hours ago

Earth’s Old Trees Keep A Record of Powerful Solar Storms

Most of the time the Sun is pretty well-mannered, but occasionally it's downright unruly. It…

23 hours ago

New Supercomputer Simulation Explains How Mars Got Its Moons

One mystery in planetary science is a satisfying origin story for Mars's moons, Phobos and…

1 day ago

The Early Universe May Have Had Giant Batteries of Dust

The largest magnetic fields in the universe may have found themselves charged up when the…

1 day ago