Caldera - Meaning, Types, Formation

A Caldera is a depression formed in volcanic peaks because of the withdrawal of magma. Many are over a kilometre wide. They are a common sight not just on Earth but also on other planets.

These depressions are formed when there is a combination of volcanic eruptions and landslides or avalanches. The events that give rise to a Caldera are some of the most terrifying on Earth. It changes the surroundings and the environment permanently.

Some Calderas get filled with water and form into lakes, like Crater Lake in Oregon, United States. Crater Lake formed thousands of years ago when Mt. Mazama erupted violently. Hawaii has active volcanic activity, and therefore several beautiful Calderas exist in the state.

There are several types of Calderas based on how they are formed. The two most common Calderas are collapse Calderas and explosive Calderas. Let’s have a look at both.

Calderas Formed Due to Roof Collapse

As the name suggests, collapse Calderas are formed when the volcanic structure collapses. This happens when magma in the volcanic mountain is emptied, and the roof of the peak cannot be supported. The roof collapses and forms a Caldera.

The Crater Lake Caldera was formed this way. Once the volcanic activity that created the Caldera subsided, a Caldera that was five miles in diameter and one mile deep was formed. Water then filled the depression and made Crater Lake the deepest lake in America.

Calderas Formed Due to Explosions

Where active volcanoes are concerned, large amounts of magma rise to the peak of the volcano. In some cases, the magma holds large gas bubbles. As the molten magma rises and comes in contact with cool air, the gas bubbles expand.

They continue expanding until they give rise to enormous explosions. These explosions blast their way through the roof of the volcanic peak, creating a large depression. This makes explosive Calderas.

Calderas Created by Supervolcanoes

Enormous volcanic eruptions are sometimes called supervolcanoes. Supervolcanoes erupt in a chain manner across very large swaths of land. One example is the Yellowstone system.

The volcanic system in Yellowstone has produced supervolcanoes with its eruptions. We can still observe the active magma activity through the hot water springs. The eruptions in this area were so massive that they produced a 50 miles wide Caldera covering the entire Yellowstone National Park.

Basaltic Caldera

Calderas formed due to shield volcano eruptions are called basaltic Calderas. These are not formed due to a single eruption but develop over time through smaller explosions. These Calderas subside gradually due to the slow release of lava from the lower parts of the volcano.

The islands of Hawaii have several impressive Calderas formed through shield volcano eruptions. Similarly, the Galápagos Islands have many shield volcanoes and basaltic Calderas.

FAQs on Caldera

Q1: What is Calderas? How is it different from a crater?

A Caldera is a depression formed due to the inward collapse of a volcano. In contrast, a crater is formed as a result of the outward explosion of rocks and other materials inside a volcano.

Q2. What are the largest Calderas in the world?

The Apolaki Caldera in the Philippines is the largest in the world. It is 150 km or 90 miles in diameter.

Q3: Give an example of a Caldera formed due to a shield volcanic eruption.

The Galápagos Islands is an example of a Caldera formed due to shield volcanic eruption. We know the Galápagos Islands for the rich display of animal and plant species. Out of these, the most significant are the Galápagos tortoise and Galápagos penguin.

Q4: How old is the Yellowstone Caldera?

Yellowstone Caldera is over 631 thousand years old.