Volcanic eruption - Causes and impact on life & nature

Volcanic eruption - Causes and impact on life & nature

Question:-Prediction of a volcano has not yet been an accurate one. Explain with the causes of a volcanic eruption. This eruption affects life and nature in ways more than one. Elaborate the reasons why it is considered a hazard.

Volcanoes are one of the natural disasters that affect human life to great magnitude. A volcano is a rupture on the earth's crust which lets out hot lava, volcanic ash, and gases through a magma chamber beneath the surface. Volcanoes on earth occur due to the seventeen major, rigid tectonic plates floating on a hotter, softer layer in its mantle.

The reasons for a volcanic eruption are:

- The release of compressed gas that causes eruptions

- Thermal compression of molten material which happens once it comes contact with water.

- Forcing out of molten material during steam eruptions.

- Occurrence of volcanic eruption is more prominent in regions where divergence or convergence of two tectonic plates takes place.

- Subduction of one plate beneath the other causes melting of rocks due to high temperature and pressure which increases along the rock
fissures.

- The diverging boundaries causes the thinning of upper crust which reduces the overlying pressure of rocks. This decreases the melting point of rocks and forms magma that rises and erupts as lava from fissure volcanos.

- Presence of mantle plumes creates hotspots causing volcanic activity.

- Presence of faults and stressing of plates cause continental volcanoes located far from plate boundaries.

Hazards:

- A volcanic activity emits lava, ash and other gases like SO2, HCL, H2S etc can cause acid rain in the surrounding area, increasing the danger to life, apart from the obvious danger from the flowing molten lava.

- The sulphate aerosols thus released react with stratospheric chlorine (from CFC), giving rise chlorine monoxide which acts as a destructive element to the ozone layer.

- The ash emitted during volcanic eruptions is dangerous to aircrafts as well.

- This thick ash may also settle on farmlands and crops thus affecting and decreasing productivity of crops.

- There is a huge loss of human life and property, basic damage caused by lava, ashes, rocks etc.

- There are times when a volcano is followed by disasters like tsunami,earthquakes, floods etc.

- Great changes take place in the atmosphere of the region along with the surrounding regions.

Reasons for difficulty in detecting a volcano:

- Almost always there is an absence of a defined sequence of events that precede an eruption.

- The subsurface phenomena occurs with an extremely high temperature due to which most scientific instruments refuse to work.

- The suddenness of the phenomena renders less time for analysis and preparation.

- The prevalent methods of using seismic analysis is not always completly reliable, although whose study presents some hints for prediction, but accuracy is missing since they are based on permutations and combinations.

- The unpredictable eruption may bring about changes in its timeline or prevent the eruption altogether.

- At present, continuous efforts are made by scientists to study a number of eruption models and by investing in better technology, they are trying to adopt new methodology in their prediction However, accuracy is likely to remain difficult to achieve.