Types of Volcanic Eruption

LET US END THIS YEAR WITH A BANG!

We're on the third lesson in this 'LET US END THIS YEAR WITH A BANG' session. We won't tell the word Bang, without any meaning. This lesson is full of explosions for we are going to learn about the different types of volcanic eruptions. What are we waiting for? Bang, bang, bang.

Mount Pinatubo (https://fthmb.tqn.com/6du9OopQNFkuu5yxXunmcRiD904=/768x0/filters:no_upscale()/Mount-Pinatubo-58c2c3ba5f9b58af5ca0ae25.jpg)

Do you remember the 1991 Pinatubo Eruption that leaves a great mark in Philippines' volcanic history. A lot of land and property were damaged because of the eruption of the volcano. There are different types of volcanic eruption and the 1991 Pinatubo Eruption belongs to the Plinian which is largest eruption.

TYPES of VOLCANIC ERUPTION

Volcanoes are classified according to the wetness or dryness of the magma's water content. These are the different types of volcanic eruption.

a. Phreatic or Hydrothermal

Phreatic Eruption

(http://www.luckysci.com/wp-content/uploads/2014/10/ontake-japan-eruption-1.jpg)

This is a stream-driven eruption as the hot rock come in contact with water. It is short-lived, characterized by ash columns but may be onset of a larger eruption.[1]

It is caused by the interaction of hot magma with surface lake water, sea water, or groundwater. The water immediately surrounding the magma is heated and volatilized. Its expansion builds up pressure on the envelope of water surrounding it. [2]

b. Phreatomagmatic

Phreatomagmatic Eruption

(https://volcano.si.edu/Photos/full/025090.jpg)

This is a violent eruption due to the contact between water and magma. As a result, a large column of very fine ash and high-speed and sideway emission of pyroclastics called base surges are observed. [1]

Unlike phreaticeruptions, the products of phreatomagmatic eruptions contain juvenile (magmatic) clasts. [3]

c. Strombolian

Strombolian Eruption

(https://volcanocafe.files.wordpress.com/2013/10/strombolian-eruption.jpg)

This is a periodic weak to violent eruption characterized by fountain lava. [1]

Strombolian eruptionsconsist of ejection of incandescent cinder, lapilli, and lava bombs, to altitudes of tens to a few hundreds of metres. The eruptions are small to medium in volume, with sporadic violence. [4]

d. Vulcanian

Vulcanian Eruption

(https://images.fineartamerica.com/images-medium-large/1-ash-cloud-from-vulcanian-eruption-richard-roscoe.jpg)

This is characterized by tall eruption columns that reach up to 20 km high with pyroclastic flow and ashfall tephra. [1]

This type of eruption results from the fragmentation and explosion of a plug of lava in avolcanic conduit, or from the rupture of a lava dome (viscous lava that piles up over a vent). [5]

e. Plinian

Plinian Eruption

(https://fthmb.tqn.com/6du9OopQNFkuu5yxXunmcRiD904=/768x0/filters:no_upscale()/Mount-Pinatubo-58c2c3ba5f9b58af5ca0ae25.jpg)

This is excessively explosive type of eruption of gas and pyroclastics, like what we have above, the Pinatubo Volcano in Zambales. [1]

Plinian eruptions or Vesuvian eruptions are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in 79 AD, which destroyed the ancient Roman cities of Herculaneum and Pompeii. [6]