【明報專訊】Volcanoes are impressive natural phenomena, but they do not often threaten us. There are about 500 active volcanoes (活火山) in the world with, on average, 10 eruptions each day. The good news is that most of these eruptions are small and manageable. People usually have enough time to evacuate (疏散). In earlier times, volcanic eruptions could be truly catastrophic (災難性的). The most famous example is the complete destruction of the ancient Roman towns of Pompeii (龐貝) and Herculaneum (赫庫蘭尼姆). In the past 200 years, volcanoes have killed more than 1,000 people.