Figure 9: Distribution of volcanoes

3.6. Effects of volcanic eruptions

Volcanic eruption causes heavy damage to human life and property. Some of them are as under:

♤ Large volumes of hot lava moving at a fast speed can bury man-made buildings, kill people and animals, destroy agricultural farms and pastures, burn and destroy forests.

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

♤ If the explosive eruption has occurred suddenly, the human beings get no time to escape to safer places. Heavy rains mixed with volcanic dust and ash cause enormous mud-flow on the steep slopes of the cones.

♤ Earthquakes caused due to explosive eruptions can generate destructive tsunamis, seismic waves, etc. These can cause loss of life and property in the affected coastal regions.

♤ The volcanic eruptions can change the heat balance of the Earth and the atmosphere, causing climatic changes.

But there are many positive effects also. Some of them are:

♤ Lava can give rise to fertile soils. Most of the precious stones are formed due to volcanic activity.

♤ Geysers and springs are tourist attraction and are also important from the medical point of view due to the chemicals dissolved in them.

♤ Some crater lakes are source of rivers and often offer scenic attraction for tourists.

♤ Most of the volcanic rocks when exposed on the surface are a storehouse of metals and minerals.