Japan’s Volcanic Geography
Japan sits at the intersection of four tectonic plates – the Pacific, Philippine Sea, Eurasian, and North American plates – creating one of the most geologically active environments on Earth. The country has approximately 110 active volcanoes (roughly 10% of the world’s active volcanoes) and is located in a subduction zone where intense geological activity produces both destructive earthquakes and a landscape of extraordinary geothermal features. This volcanic heritage is simultaneously a source of risk and of some of Japan’s most remarkable scenery.
The relationship between volcanic activity and daily life in Japan is intimate and practical: geothermal heat powers the ubiquitous onsen (hot spring) bathing culture, volcanic soils support some of Japan’s most productive agriculture, and volcanic mountains from Fuji to Aso provide iconic landscape references. The word jigoku (hell) is regularly applied to volcanic steam vents and boiling mud pools – not as metaphor but as literal description of the appearance of these features – and has given its name to specific tourist sites in Beppu, Noboribetsu, and Jigokudani.
Beppu: Geothermal Spectacle
Beppu City in Oita Prefecture, Kyushu, is Japan’s most concentrated geothermal tourist destination, producing more hot spring water than any other location in Japan. The Beppu Jigoku (Hells of Beppu) are a series of spectacularly active hot spring pools open for viewing – not bathing – that demonstrate the range of geothermal phenomena. Blood Pond Hell (Chinoike Jigoku) is coloured deep red by iron and clay minerals. Sea Hell (Umi Jigoku) is vivid cobalt blue from the mineral content and temperature (approximately 98 degrees Celsius). Tornado Hell (Tatsumaki Jigoku) is an intermittent geyser. Monster Mountain Hell (Oniyama Jigoku) contains hot spring-fed ponds used to raise crocodiles.
Beyond the Jigoku spectacle, Beppu’s bathing culture is genuinely exceptional: the city has over 2,800 hot spring sources and dozens of public bathhouses (kokumin sento and onsen facilities) accessible for ordinary bathing at modest cost. The sand bath (sunahafuro) at Beppu Beach Sand Bath is a distinctive experience in which bathers are buried in naturally heated volcanic sand by attendants.
Noboribetsu and Hokkaido Geothermal Sites
Noboribetsu Onsen in Hokkaido’s Shikotsu-Toya National Park is centred on Jigokudani (Hell Valley) – a steaming volcanic crater with sulphur-yellow ground and active vents from which the mineral-rich waters feeding the resort’s baths are drawn. Walking paths allow close observation of the active geothermal surface, and the contrast between the barren, steaming crater and the surrounding forest is visually dramatic. The resort hosts multiple ryokan drawing from different spring sources, with water temperatures and mineral compositions varying enough to create meaningfully different bathing experiences.
The Akan caldera lake complex in eastern Hokkaido, containing Lake Akan (home of marimo spherical algae), Lake Mashu (one of the clearest lakes in the world), and Lake Kussharo, sits within a region of persistent geothermal activity. Sulphur-producing vents are visible along the Kussharo lakeshore in winter, where wild Japanese whooper swans gather in the warm water near the vents.
Mount Aso and Kyushu Volcanoes
Mount Aso in central Kyushu contains one of the world’s largest calderas (25 kilometres across) and an active central cone (Nakadake) that remains open to visitors when volcanic activity permits – which varies significantly week to week. When the crater is accessible, the views into the active smoking caldera and across the vast outer rim are extraordinary. When volcanic activity is elevated and the crater is closed (as has been frequently the case in recent years), the outer caldera rim and the grassland-covered inner caldera floor remain scenic destinations. The Aso area is also culturally significant for its Aso Shrine traditions tied to the volcanic deity.