Volcano Eruption

The eruption of lava from a volcano occurs when hot materials from the Earth’s interior are ejected from the volcano’s vent. Volcanic eruptions can occur from either the side branches or the summit of the volcano. Some eruptions are violent explosions that eject massive amounts of rock and volcanic ash into the atmosphere, causing widespread devastation and the death of a large number of people. Some of the lava flows are quiet, while others are raging. Volcanologists have identified a number of more complex types of volcanic eruptions that have occurred. These are frequently named after well-known volcanoes where that particular type of eruption has occurred. During a period of activity, some volcanoes may only produce one type of eruption, whereas others may produce a variety of types in a series of eruptions.

Eruption of Volcanoes

As magma is lighter than the solid rock surrounding it, magma rises to the surface and collects in magma chambers as it cools. Finally, some of the magma is able to push its way through the earth’s surface through fissures and vents. As a result, a volcanic eruption occurs, and the magma that is emitted is referred to as lava.

To understand how volcanoes erupt, we must first comprehend the structure of the Earth. The lithosphere is the outermost layer of the Earth’s crust and mantle, and it is located at the top of the layering structure. In mountainous areas, the thickness of the crust varies from 10km to 100km, with silicate rock constituting the majority of the crust.

What Causes Volcanoes to Erupt?

Individual seismological characteristics determine which sections of the Earth’s mantle are found within the crust and how they are classified. The upper mantle has a range of 8 – 35 kilometres to 410 kilometres; the transition zone has a range of 400 to 660 kilometres; and the lower mantle has a range of 660 to 2891 kilometres.

When you move from the crust to the mantle, the conditions change dramatically. The pressures and temperatures skyrocket, reaching temperatures of up to 1000 degrees Celsius. This viscous and molten rock collects in large chambers deep within the Earth’s crust, where it remains for millions of years.

Because magma is lighter than the surrounding rock, it rises to the surface and seeks out cracks and weaknesses in the mantle as it makes its way to the surface. After reaching the surface, it finally explodes from the volcano’s crater’s crater’s peak point. It is known as magma when it is located beneath the surface of the earth and erupts as ash when it is brought to the surface.

Every eruption results in the formation of a wall of rocks, lava, and ash across the volcanic vent. The viscosity of the magma has a significant influence on the nature of the eruption. When the lava flows easily, it travels a long distance and generates broad shield volcanoes. When it becomes too thick, it takes on the shape of a familiar cone volcano. If the lava is extremely thick, it has the potential to build up inside the volcano and explode, forming what is known as a lava dome.

Volcanic eruptions are classified into several categories.

Vulcanologists have distinguished between several types of volcanic eruptions, during which lava, tephra (ash), lapilli (volcanic bombs and volcanic blocks), and various gases are expelled from a volcanic vent or fissure. Lava eruptions are the most common type of volcanic eruption. These are frequently named after well-known volcanoes where this type of behaviour has been observed in previous eruptions. A period of activity at some volcanoes may be characterised by the eruption of only one characteristic type, whereas others may be characterised by the eruption of an entire sequence of types in one eruptive series.

There are three different types of eruptions:

• Magmatic eruptions are the most well-documented type of eruption because they occur most frequently. They are caused by the decompression of gas within magma, which causes the magma to move forward.

• A phreatic eruption is caused by the superheating of steam that occurs as a result of contact with magma. This type of eruption frequently does not result in magmatic release, but rather results in the granulation of existing rock.
• It is the compression of gas within magma that causes phreatomagmatic eruptions to occur, which is the polar opposite of the process that drives magmatic activity.

Mechanism of eruption

Eruptive volcanic activity is triggered by few main mechanisms:

• Magmatic eruptions are caused by the release of gas during decompression.

• Steam eruptions that result in the ejection of entrained particles, which causes phreatic eruptions

• Phreatomagmatic eruptions are caused by thermal contraction caused by chilling when in contact with water.
• Expansive eruptions, which are the most active, are distinguished from effusive eruptions, which are less active. Explosive eruptions are characterised by gas-driven explosions that propel magma and tephra into the air and into the atmosphere. The outpouring of lava that occurs during effusive eruptions, on the other hand, does not result in any significant explosive eruption.

Volcanic eruptions can be extremely powerful or extremely weak. Excessive Hawaiian eruptions, which are characterised by lava fountains and fluid-flowing lava flows, are one extreme. However, these eruptions are not typically considered to be particularly dangerous. Plinian eruptions, on the other hand, are large, violent, and extremely dangerous explosive events that occur in large quantities. Unlike earthquakes, volcanoes are not limited to one type of eruptive style, and they frequently display a variety of eruptive styles, both passive and explosive, over the course of a single eruptive cycle. As a result of this, volcanoes do not always erupt vertically from one single crater near their summit, as is commonly believed. Some volcanoes have lateral and fissure eruptions, which are particularly dangerous. Particularly notable is that many Hawaiian eruptions begin in rift zones, and some of the most powerful Surtseyan eruptions occur along fracture zones. Previously, scientists believed that magma pulses mixed together in the magma chamber before ascending to the surface, a process that would take several thousands of years according to estimates. A team of volcanologists from Columbia University, however, discovered that the eruption of Costa Rica’s Irazu Volcano in 1963 was most likely triggered by magma that travelled nonstop from the mantle over the course of a few months.

Conclusion

Volcanoes are ruptures in the crust of our planet Earth that allow hot gases, molten lava, and some rock fragments to erupt by opening and exposing the magma that lies beneath the surface of the Earth’s crust. Deep within the earth, the temperature is so high that some rocks slowly melt and turn into a thick, flowing substance known as magma. Because it is lighter than the solid rock surrounding it, magma rises to the surface and collects in magma chambers as it cools. Finally, some of the magma is able to push its way through the earth’s surface through fissures and vents. As a result, a volcanic eruption occurs, and the magma that is emitted is referred to as lava.