The Earth’s explosive skin condition...

More than half a billion people throughout the world live near a volcano. Volcanoes are usually surrounded by fertile farmland, and cheap energy is often easily available. On the other hand, volcanoes are temperamental, and nobody knows exactly when the n

Volcanoes are Earth's natural relief valves. When too much magma is under too much pressure close to Earth’s crust, a volcano develops – or an existing one erupts one more time. There are volcanoes on all continents, including Antarctica but the majority of the volcanoes in the world are located in places, where the tectonic plates meet. Their most frequent occurrence is the “Ring of Fire” in the basin of the Pacific Ocean.

The exact number of volcanoes is unknown, as it depends on how you define a volcano – whether it must be active, and if all craters in major volcanic areas count as separate volcanoes. It is estimated that 1,300-1,500 volcanoes exist that have erupted over the past 10,000 years. Moreover, there is a large quantity on the bottom of the oceans. Some volcanoes are only a crack in the ground, while others develop over millions of years, ending up as the South American Ojos del Salado, which rises to an altitude of almost 6.900 m, making it the world’s highest volcano.

Just like sizes and shapes of volcanoes, their temper is determined by the type of magma which powers them. Some magma flows easily out of the crater and down slightly inclining slopes. Other types are viscous, flowing with much more difficulty, possibly causing "constipation", i.e. almost acting as a plug. Volcanoes with highly viscous magma are ticking bombs. If the pressure keeps on rising below the plug, the volcano will end up exploding in an inferno of fire, glowing red-hot magma, and ash.