雲仙岳
Throughout its history, Shimabara has been dominated by the seismic activity of Mount Unzen. A major volcanic eruption in 1792 resulted in a tsunami that destroyed most of the town and killed over 15,000 people, in one of Japan's worst volcanic disasters. In more recent history, major eruptions in 1990–1991 resulted in pyroclastic flows, which killed 43 people and forced the temporary evacuation of hundreds of others. The 5th International Conference of Cities on Volcanoes was held in Shimabara on November 19–23, 2007.