- The earth is made up of various layers like an onion. The thickest layer of it is called Mantle. You can reach the mantle if you travel for around 30 kilometers 'into' the earth. The temperatures at the mantle are really high varying from 1,000 - 7,000 degrees depending on the depth and condition of the mantle.
- Though the temperatures at mantle are enough to solve even a rock, it remains mostly solid due to the high pressure prevailing over its surface. But if some part of it is bound to melt and also has a crack to reach the surface of the earth... that's called a VOLCANO!
- Depending on the activity of a volcano, it's classified into Active, Dormant or Extinct Volcano. An active volcano is one which has erupted in recent history. A dormant is the volcano, which has not shown any signs of danger for thousands of years together. An Extinct volcano is the one which has no chance to erupt again.
- Geologists have estimated that almost 1300 volcanoes have erupted in the previous 10000 years of earth's timeline. And more than 4000 volcanoes might have erupted underwater. There are more volcanoes in the depth of oceans, because there is a higher chance of a weak spots between the tectonic plates that cover the ocean's surface. Underwater volcanoes though invisible to the human eyes can create a tsunami!
- Like cyclones and earthquakes, the severity of volcanoes was also measured basing on their eruptions. The highest position on the scale is no. '8'! If a volcano spreads its magma for more than 1000 cubic kilometers, it's placed on no.8 of the scale. A volcano named TOBA in the country of Indonesia has made such huge eruption around 74,000 B.C. Its impact was so huge on the nature that the earth has gone into an ice age for 1000 years!
-There is only one volcano in India which is active. It lies on the Barren Island which is a part of the Andaman Island! India might be lucky in case of Volcanoes. But certain portion of Pacific Ocean which is called `The ring of fire` is a place of huge volcanic activity. 75% of the volcanoes and 90% of the earthquakes occur at this place. Countries like Japan and Indonesia which lies in this place are the worst sufferers.
- The molten rock in the earth's crust is called MAGMA and when it reaches the surface through a volcano, it's called lava. The lava when cools down, becomes a rock again! Almost 80% of the surface we walk on is the result of some volcanic eruption.
- World's tallest Volcano 'Mauna Kea' lies in the island of Hawaii which is in the Ring of fire. Though it measures around 13,796 feet from the sea level... much of it is submerged in the ocean. If we measure the complete mountain from its base, it would stand at a massive height of 33000 feet!