How old are Beppu’s hot springs?
Beppu’s hot spring system, meaning its entire network of underground, geothermal spring water, is believed to be approximately 50,000 years old. The city has the largest spring water output volume of any hot spring town in Japan. Two factors contribute to this volume: local volcanic activity and an alluvial fan topography that allows rainwater to easily penetrate into the ground and be stored.
Not all volcanoes provide nearby towns with abundant sources of hot spring water. The famed Mt. Fuji, for example, is the nation’s largest volcano. Yet most of its groundwater flows out in springs at the mountain’s base and is not stored underground long enough to be heated by geothermal activity. Beppu has succeeded as a hot spring destination because of the area’s volcanic activity and suitable geography.