Beppu is a city in Japan located on the island of Kyushu, surrounded by the sea on one side and high mountains on the other. What sets Beppu apart from all other cities in the world is the incredible number of thermal springs.

Beppu is the home to more than 2500 hot spring vents. Almost each vent is a home to an Onsen (hot spring bath).

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.

The highland region spouts fumaroles and hydro-thermal water, whereas the lowland region bears hot spring water of diverse chemical composition. The range of phenomena and the regularity of their spatial alignment is a characteristic of the Beppu hotspring field.

How many types of hot spring water are found in Beppu?

Beppu has seven of the ten hot spring types officially recognized by the Japanese government. Several factors contribute to the properties of the hot spring water. Rainwater stored underground mixes with hot water deeper in the earth and also reacts chemically with underground rock layers. The complex topography and composition of the earth underneath Beppu, as well as local volcanic activity and proximity of the sea, also contribute to the diversity of the area’s spring water. Beppu’s seven spring types are believed to deliver various benefits. Simple springs are said to promote better sleep. Hydrogen carbonate springs, chloride springs, and sulfate springs are said to warm the body and moisturize the skin. Sulfur springs and acidic springs are believed to improve skin condition. And ferruginous springs, which contain iron, can be drunk to supplement the mineral in one’s diet. In addition, experts believe that carbon dioxide springs are present in the area and have been searching for their sources in cooperation with the city of Beppu. (Beppu does not have radioactive springs or iodine-containing springs.

Due to the high topographic relief, many sites of active and extinct surface alternation are scattered from 1300 m to the sea. In the highest part (900 m to 200 m), acid-type surface manifestation like fumaroles, steaming ground, solfatara, and mud pools, develop intense silicification and advanced argillic alteration. In the intermediate part (200 to 100 m), the near-surface boiling of thermal fluids is expressed as warm or steaming ground, mud pools, hot springs which develop an argillic alteration type and limited silica sinter depositon. Development of an argillized cover leads to occasional hydrothermal explosions and mud volcanoes. The lower part of geothermal field (100 m to the sea) is characterized by the presence of now-extinct hot springs.

One of Beppu’s most popular hot spring water attractions is the otherworldly Hells of Beppu. It is a collection of seven bubbling onsens spread across the Kannawa and Shibaseki District. The seven hot spring pools include Umi Jigoku, Onnishi Bozu Jigoku, Shiraike Jigoku, Kamado Jigoku, Oniyama Jigoku, Chinoike Jigoku, and Tatsumaki Jigoku.

Of all the eight infernal lakes, the ‘Bloody Lake’ stands out the most, a thermal spring about 30 meters deep, with water that reaches temperatures of up to 78 ℃. Due to the large amount of iron in the water, the ‘Bloody Lake’ has a bright red color. In addition, boiling water is released every 35-40 minutes, giving the pond a very mystical and scary look.

Other popular springs are Shiraike Jigoku (White Hell Pond) hot spring known for its milky appearance that seems more blue-green than white. The spring is surrounded by manicured Japanese gardens and a small aquarium featuring 16 types of tropical fish, including piranhas, Tatsumaki Jigoku (Hell Geyser) which erupts every half hour. Known as “tornado hell,” Tatsumaki Jigoku has the hottest of waters among the springs of the Hells of Beppu, with temperatures reaching a staggering 150 degrees celsius.Umi Jigoku (Hell Sea) is a cobalt blue 200 meters deep thermal spring. Umi Jigoku’s surrounding gardens and ponds are filled with an incredible range of plant species, including the Amazon water lily, which holds up to 20 kilograms.

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.