Facts about volcanoes

What is a volcano?
Volcano is a mountain but it has a crater (giant hole).  This crater helps in the molten rock and gases below the surface of earth, to erupt.

What is volcanic eruption?
When the volcano erupts, the magma from inside comes out which is called as lava. 

How many volcanoes are there in the world?
There are more than 1500 volcanoes in the earth.

What is the theory of plate tectonics?
The theory that the earth’s surface is broken up in to large slaps or plates.  These plates fit together like a jigsaw puzzle.  When these plates move they cause earthquakes and volcanic eruptions.  This theory is called plate tectonics.

What gases do volcanoes emit?
Volcano eruptions release different types of gases are carbon dioxide,  water,  sulphur dioxide, hydrogen chloride and hydrogen fluoride.  These gases are poisonous and cause damage.  The gases also deposit many colorful minerals after they cool down.

What kinds of rocks do volcanoes make?
Volcanoes make different types of rocks.   Examples of rocks from volcanoes are black shiny rocks called basalt, white shiny rock called pumice, and others.  These rocks are rich in minerals.

What is magma and lava?
Magma is liquid rock inside the volcano.  Lava is liquid rock (magma) that flows out of a volcano.

What are the typical temperatures of lava?
Lava temperatures range between 1,300oF to 2,200oF (700oC to 1,200oC) and glows red hot to white hot as it flows.

Are there volcanoes under the sea?
Yes, there are many volcanoes under the sea.  Some estimate that there are about 10,000 volcanoes under the sea but they are hidden under  the sea.

How old are volcanoes?
The oldest volcano is known to be Etna and is about 350,000 years old.   Other volcanoes are around 100,000 years old.

Are there volcanoes on other planets?
Yes there are in other planets for an example: Mars.


Volcano rock

This is a specimen of pahoehoe lava.

Volcano rock

This is a volcanic rock called a volcano bomb.

Pyroclastic Ash

This is a pyroclastic ash deposit.

Volcanoes on other planets

Volcano on the moon of Jupiter.  Picture taken by Voyager.