Mount Unzen erupted in 1792 and triggered Japan’s deadliest volcanic disaster, including a giant tsunami.
Mount Unzen is a volcanic complex on Japan’s Kyushu Island. During the 1792 eruption, activity shifted toward Mount Mayuyama, where a large landslide collapsed into Ariake Bay. The resulting tsunami devastated nearby coastal communities and killed about 15,000 people.
The disaster is often called the Shimabara catastrophe, after the nearby city and peninsula. It demonstrates that volcanic danger does not come only from lava or ash: earthquakes, slope failures, and water displacement can greatly expand the impact of an eruption.
Unzen became internationally significant again in the early 1990s. A lava dome grew during the 1990–1995 eruption, generating dangerous pyroclastic flows. In 1991, forty-three people, including volcanologists and journalists, died in one such flow.