Volcanoes!

Volcanoes can change the course of history. On 24 August 79 Ad the Roman towns of Pompeii and Herculaneum were laid waste by eruption of Mount Vesuvius, which cost many thousands of lives. In April 1815, Indonesia's Mount Tambora erupted with such force, fine particles floated into the northern hemisphere by the next year and caused "the year without a summer" in parts of North America and Europe, leading to crop failure and starvation. On 27 August 1883 the Indonesian volcano Krakatoa literally blew its top, causing the deaths of around 36,000 people. And the threat to human life from these types of events happening in the future remains the same. That's because there's no way of preventing volcanic eruptions. The forces lying dormant in the earth are too powerful. The only way of protecting people is to evacuate them in time. Luckily, most eruptions give us some degree of advanced warning.

"The heat is on. Beautiful and terrible in equal measure -- volcanic eruptions demonstrate the power of nature"

By the numbers

• Magma shoots out the ground at temperatures as high as 1200 degree Celsius. 
• In 1815 the eruption column from Mount Tambora in Indonesia reached a height of about 60 kilometers. There was complete darkness for three days afterwards within a 500 kilometer radius of the eruption.
• Approximately 260,000 people have died over the last 400 years as a result of volcanic activity. 
• Lava flows have been recorded at speed of up to 75 kmph. 
• On average, there are about 60 volcanic eruptions every year, many of which area in Asia. 
• The sound of the Krakatoa eruption in Indonesia in 1883 could be heard more than 3000 kilometers away in Australia.

Excess pressure

The earth's mantle on which we're standing may seem solid but is in fact floating on a sea of hot, molten rock. In places where the earth's crust is torn apart by the shifting of continental plates, magma can force its way upwards, leading to the birth of a volcano. During major eruptions several cubic kilometers of rock are brought to the surface.