Smoke and ash spews out of Mount Aso in Kumamoto Prefecture on April 16.
© Japan Meteorological AgencySmoke and ash spews out of Mount Aso in Kumamoto Prefecture on April 16.
An eruption was observed on Mount Aso in Kumamoto Prefecture about 6:28 p.m. on April 16, according to the Japan Meteorological Agency, the first in two and a half years.

From about 1:30 p.m. on April 14, the agency detected volcanic tremors at Mount Aso had begun intensifying and a large volume of volcanic gas was also being emitted.

The alert level for Mount Aso was raised from the lowest 1 to 2, meaning restrictions would be placed on approaching the crater.


The local volcano deliberative council restricted entry within a kilometer of the No. 1 crater of the Nakadake peak of Mount Aso.

At one time on April 16, fumes and ash reached a height of 200 meters, but the JMA said the eruption was not continuing as of 7 p.m.

Aso's last major eruption occurred on Oct. 8, 2016, when large boulders were sent flying down a crater and a towering plume of smoke and ash rose to more than 10,000 meters. That was the most violent eruption recorded in about 30 years and came about six months after a series of earthquakes shook a large part of Kumamoto Prefecture.