ABSTRACT
There are some 500 active volcanoes in the world; about 50 erupt in an average year. Despite a dramatic appearance and high public profile, volcanoes create far fewer disasters than do earth - quakes or severe storms. More than half the deaths recorded in the twentieth century occurred in just two events. The 1902 eruption of Mont Pelée, on the island of Martinique in the West Indies, killed 29,000 people in the port of Saint Pierre, leaving only two known survivors, whilst the 1985 eruption of Nevado del Ruiz in Colombia claimed a further 23,000 lives. It is normal practice to classify volcanoes as active, dormant or extinct. But the infrequency of major eruptive events is one of their most dangerous features and in 1951 Mount Lamington killed 5,000 people in Papua New Guinea, despite being considered extinct (Chester, 1993). To be prudent, all volcanoes that have erupted within the last 25,000 years should be regarded as potentially active. Most are located in geologically unstable areas and prone to mul - tiple threats (Malheiro, 2006). On the other hand, volcanic terrain provides important natural resources, including geothermal energy, building materials and opportunities for tourism.
