Volcanoes

• © UNESCO/Dominique Roger
• Poas volcano in eruption

Volcanic eruptions are the one form of natural disaster that comes with a warning. Hot molten rock generates earthquakes and causes the ground to swell as it makes its way to the surface. Provided the volcano is being monitored, such signs become apparent weeks or even months before any volcanic activity. But there is no way of telling in advance how catastrophic an eruption will be or how long it will last. And sometimes the warning signs turn out to be false alarms. This and the lack of means in developing countries explain why only a few of 800 active and 500 potentially active volcanoes are monitored on a regular basis.

Because eruptions are predictable, it is usually possible to move populations at risk and reduce or prevent loss of life. But little can be done to control damage to crops or property caused by mud-flow, lava-flow and ash deposits once an eruption is under way.

Volcanoes play a fundamental role in life's sustainability on earth, and eruptions ought not to be disasters. The fact that they sometimes are is almost entirely the result of inappropriate settlements in risk-prone areas.
More