The eruption was recorded at 20:05 local time (11:00 GMT), when the volcano spewed a column of ash and smoke to a height of 2.5 kilometers (1.5 miles).
The meteorological agency warned people in the districts of Arimura-cho and Furusato-cho in the Kagoshima Prefecture that large volcanic stones may fall within a radius of 3 kilometers from the crater. The office also did not rule out the risk of a pyroclastic flow.
Authorities of the city of Kagoshima raised the alert to the highest level, which implies evacuation of the population from affected areas.