How Are Volcanoes Formed?

There are actually a number of different types of volcanoes. Different volcanoes are formed in different ways. The majority of volcanoes are formed when two of the Earth’s plates meet and collide.

These volcanoes actually occur on the ocean floor. When the plates then move apart from each other, a gap or a “hole” is created between the plates. When this gap or hole is created, molten rock rises between the gaps.

If the amount of magma is significant enough, then the magma rises above the surface of the ocean. This is known as an island. When the two plates collide and one plate forces the other plate beneath it, a different reaction occurs.

If this happens, then the friction that is caused during this reaction makes the plate that is beneath the other plate melt. This then causes magma to rise up, and this creates a volcano. The volcanoes that form by this method are usually the most dangerous and the most volatile ones.

Formation of Other Types of Volcanoes

Shield Volcanoes

One type of volcano is called the “shield volcano.” Shield volcanoes are extremely broad and flat when compared to other volcanoes.

Their shape is created by a significant amount of lava running down the surface of the volcano, and then cooling. The eruptions of shield volcanoes aren’t as severe as other volcanoes. When a shield volcano erupts, gases escape and the lava rise to the surface to gently flow down the sides of the volcano.

Composite Volcanoes

Composite volcanoes, also known as strato-volcanoes, are formed by alternate layers of rock fragments and lava. The shape of a composite volcano is large and cone-like. Unfortunately, the eruptions of composite volcanoes are quite explosive and dangerous because in a composite volcano, magma tends to clog the crater pipe. When the magma clogs the crater pipe, the gas in the volcano is trapped inside. The trapped gas rises in pressure, until the pressure becomes too much for the magma that is clogging the volcano. An explosion subsequently occurs.

Caldera Volcanoes

Caldera volcanoes are formed from considerable amounts of magma erupting from sub-surface magma chambers. When the magma erupts, it leaves an empty space below the surface. The top collapses into this empty space, and this forms the caldera volcano.

The eruption of a caldera volcano generally has the coolest lava. The temperature of the lava ranges from between six hundred and fifty degrees Celsius to eight hundred degrees Celsius. These types of volcanoes are actually the most dangerous. This is because when a caldera volcano erupts, it frequently results in a number of additional hazards. For example, a caldera volcanic eruption might also cause tsunamis, large pyroclastic surges, and widespread falls of ash.

Decade Volcanoes

Some of the most famous volcanoes on the planet are referred to as the Decade Volcanoes. The Decade Volcanoes refers to sixteen volcanoes that have been identified by scientists as noteworthy due to their large eruptions, and their closeness to populated areas.

The sixteen Decade Volcanoes currently are:

Avachinsky-Koryaksky in Russia
Nevado de Colima in Mexico
Mount Etna in Italy
Galeras in Colombia
Mauna Loa in the United States
Mount Merapa in Indonesia
Mount Nyiragongo in Africa
Mount Rainer in the United States
Sakurajima in Japan
Santa Maria in Guatemala
Santorini in Greece
Taal Volcano in the Philippines
Teide in Spain
Ulawun in New Britain
Mount Unzen in Japan
Mount Vesuvius in Italy

Thus, now that you know a little more about how are volcanoes formed, you can continue to research the topic yourself. Learn all about these fascinating threats!