[Geography Notes] on Calderas Pdf for Exam

Natural processes take time to occur and have various stages. Volcanic eruptions are one such type. During the eruption, magma present underneath comes out, the volcano explodes, and hence there is no boundary support left behind. Thus there are no sides and top of the volcano anymore as they fall inward with no support between. This depression formed due to magma eruption forms caldera. As a result, we either get steep cliffs around or lakes formation. These are huge-ranging up to 100 km in diameter. These are generally oval or circular. These have different depths, sizes, and shapes. 

Caldera Volcano

The word ‘caldera’ is associated with a volcano’s huge eruption, which can eventually have different sizes, depths, and shapes. As a result of the eruption, we get a large amount of magma expelled out on the earth’s crust. This hollow cavity on the earth’s surface is sometimes referred to as a crater. However, the two are not the same. It is because a crater is formed with the subsequent collapse. 

In the entire world, there have been seven known caldera volcanoes since the 1900s. The word is taken from the Spanish language, which means cooking pot. Also, this circular fracture is called a ring fault. 

Caldera Volcano Examples

A significant depression on the earth’s surface, let ground above the hollow part, is the caldera Volcano. However, different types vary according to size and shapes. Let us study some of them. 

Stratovolcanoes are the most explosive types which form crater-lake calderas as a result. These are caused by Plinian eruptions, which cause colossal lava, rocks, and ash to move out of the earth. One such example is Crater Lake in the US, Oregon which is not a crater that took 7000 years to form. 

Shield Volcanoes do not explode at one time. They undergo several stages and take a lot of time to pull magma out. Usually, these are characterised as lava fountaining and are less explosive. Unlike Crater-lake types, these produce nested depression on the earth’s surface. These are generally small and less than 5 km in diameter. The islands of Hawaii have good examples of shield volcano calderas. 

These are the largest depressions running from 15 to 100 km in diameter. These are not formed by a single volcano but result from different volcanic eruptions that collapse several magma chambers. These are the most destructive types that take thousands of years to form. Toba Caldera on the Indonesian is the best example of resurgent calderas with a rough figure of 74,000 years of formation. 

Some Other Caldera Volcano Examples

• The Yellowstone Caldera: 

It is named after its location- Yellowstone National Park, the US, where Yellowstone SuperVolcano erupted. It is a complex type that took 64,000 years to form.

It is a crater-lake type located at Antarctica’s off coast with a rough figure of 10,000 years formation. It has resulted in lake formation after seawater flooded inside it. 

This island has a series of shield volcanoes that finally resulted in the most profound hole formation. 

It has an elliptical-shaped oval depression known for the largest collapsing with magma eruption. 

Crater and Caldera

Usually, people mix the two terms, Crater and Caldera, with each other. When a crater is formed, you cannot get to the largest part. Thus the change from the deepest depression to crater is irreversible. 

What is a Crater in a Volcano?

When a volcano erupts, it brings different shapes and sizes. If it is a bowl-shaped depression on the earth’s surface, it is called a crater. These volcanic eruptions have steep and deep sides. As a result, a crater is formed. Craters are formed when magma or rocks from a volcano moves out and leaves behind hollow inside. There are generally Summit craters and Flank craters formed as a result of the eruption.

Difference Between Crater and Caldera

People usually confuse between a crater and caldera, but both of them are opposite. The crater is caused when volcanic eruptions cause hollow inside, letting magma out. On the other hand, the deep hollow collapses to form large craters. Craters are generally small and have small features, but giant holes are referred to as calderas.