Mount Aso — Nakadake Crater (中岳火口) 中岳火口
400×900 m: in the crater's emerald-green lake the water is at 50–60°C, and strongly acidic.
Nakadake is one of the five central peaks (阿蘇五岳) inside the great Aso caldera, and its first crater is among the most closely monitored volcanoes in Japan: sulphurous gas, seismic tremor and the colour of the crater lake are measured every day. The area lies within Aso-Kuju National Park, established in 1934 (as 阿蘇国立公園, renamed in 1986), and within the Aso UNESCO Global Geopark, recognised in September 2014. 2026 was a year of high alert: the level rose to 3 (entry ban, 2 km radius) on 14 August, after an increase in sulphurous gas and volcanic tremor, and went back to 2 on 1 September at 16:00, with the restriction reduced to about 1 km from the crater from 9:00 the next day, when access up to the plaza also became possible again.
Kumamoto
Aso Sanjo Terminal
