Effects of Volcanic Eruption: Constructive and Destructive – Class 9

The term Volcano comes from ‘Vulcan’ – the Roman God. The volcano is an opening or a vent through which heated materials erupt from the highly heated interior to the surface of Earth. These Eruptions can have different features and their effects can be good or bad. Let us learn about the bad and good effects of volcanic eruption.

Volcanoes are Earth’s geologic architects, but wrathful ones, they love to destroy as much as they like to create.

Effects of Volcanic Eruption

Whenever we hear of any volcanic eruptions, our mind paints a picture of hot molten lava flowing out, destroying civilizations and killing lives. However, the effects of these eruptions are far-reaching and wide and some of them flow into the actual good of nature too.

Constructive Effects of Volcanic Eruption

1. Numerous types of Landforms are created due to the cooling and solidification of magma below the Earth’s surface and the solidification of lava on the Earth’s surface. The Landforms created on Earth’s surface are called Extrusive Landforms. These include volcanic plateaus, volcanic mountains, and volcanic plains.

Geysers and Hot Springs formed due to volcanic activity are very useful for health as they contain Sulphur and other dissolved minerals.

2. The lava and ash deposited during eruptions provide valuable nutrients to the soil and create fertile plains, which are good for agriculture. Examples of such plains are North-west Deccan in India and parts of Brazil.

3. All precious stones are formed within volcanoes. For example-Diamond in South Africa and Nickel deposits of Sudbury in Canada.

4. The Crater Lake serves as a great source of perennial rivers. For example, Lake Volcanic in South Africa.

5. Volcanic eruptions form dramatic sceneries and hence are of great tourist interest.

6. Most of the volcanic rocks when exposed to the surface are a storehouse of metals and minerals.

7. Sometimes remnants of volcanoes after erosion help in preserving traces of Old civilization.

Destructive effects of Volcanic Eruption

1. Most of the latest volcanic areas are absolutely barren and inhabited by man. The high porosity leads to immediate percolation and the disappearance of rainwater. Thus no human activity is possible here.

2. Volcanic eruptions are disastrous causing complete destruction. Eruptions often force people living near volcanoes to abandon their land and houses, sometimes forever.

3. Volcanic activity since 1700 AD has killed more than 260000 people, destroyed entire cities and forests, and severely disrupted local economies for months to years. The volcanic eruption of Mt. Krakatoa in 1883 caused the destruction of almost the entire island.

Some scientists believe that the fall of volcanic materials caused the mass extinction of a few animal species, including the extinction of dinosaurs.

4. Tsunami or tidal wave is a result of volcanic eruption or Earthquake. It causes severe damage. Also, these Tsunamis carry a lot of energy and when they hit the coast, strong currents can cause massive erosion of the coastlines as well as tear apart buildings they encounter.

5. Volcanic eruptions can change the heat balance of the Earth and the atmosphere, causing global warming.

6. The fall out of large quantities of fragmented materials, dust, ash, and smoke creates health hazards due to poisonous gases emitted during eruptions. It also causes acid rain.


1. What serves as a great source of perennial rivers?
(i) Volcanic plains
(ii) Volcanic Mountains
(iii) Volcanic deltas
(iv) Crater lakes

2. Which of these is a plain made by lava and ash deposits?
(i) The northern plains of India
(ii) Tabasco plains of Mexico
(iii) Sahara desert
(iv) North-west Deccan Plains

3. Volcanic plateaus, volcanic mountains, and volcanic plains are examples of what?
(i) Intrusive landforms
(ii) Fertile landforms
(iii) Hilly landforms
(iv) Extrusive landforms

4. Geysers and Hot Springs contain mainly which mineral?
(i) Phosphorous
(ii) Potassium
(iii) Sodium
(iv) Sulphur

8. Nickel deposits of Sudbury in Canada were formed where?
(i) Inside the ocean
(ii) Inside the lake
(iii) Inside plateaus
(iv) Inside volcanoes

Read More: What is Thunderstorm? Definition and Precaution – Science Class 7

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