12. The Mt. Unzen Disaster: A Terrible Learning Experience

Mount Unzen is an active composite stratovolcano in the Southwest Japan Arc. It is made up of a cluster of overlapping volcanoes that have formed at various times over the past 6 million years on the Shimabara Peninsula of Kyushu Island. This complex is close to the major cities of Nagasaki and Kumamoto and has considerable settlement around it on the peninsula. Of course, communities of human beings have always lived on volcanoes and their surrounding landscapes, whether active or dormant. These volcanoes provide visitors to such communities with access to their geological history and have even provided the remains of previous settlements now covered by eruptions (e.g., Pompeii (Vesuvius AD79) and Soufrière Hills (Montserrat). As a representative of the most dangerous of these volcanoes, Mt. Unzen became a worldwide media sensation in 1991 when it produced a series of massive eruptions (which claimed 44 lives) after many years of calm. This event raised concerns about community awareness of volcanic activity and created new opportunities for the study of major volcanic events and their precursors. From this situation, some of the more destructive volcanoes have been classified as requiring constant monitoring (the Decade Volcanoes), while calls for more information on all those identified as active (and, more recently, on those considered dormant given several occurrences of reactivation that were not considered likely) are frequently made.