After observing an increase in the number of volcanic earthquakes, the Meteorological Agency has warned of a possible small eruption at Mount Io, which straddles the prefectures of Miyazaki and Kagoshima.
The local government in Ebino on Sunday declared a 1-km-radius no-entry zone around the crater of Mount Io, part of the Kirishima mountain range, while the agency said that large stones could be ejected within a 1-km radius in the event of an eruption.
The agency detected 53 volcanic temblors by 7 p.m. Sunday at the 1,317-meter-high volcano, the highest per day since seismometers were installed there in March 2013.
Volcanic activity has intensified since last year, the agency said. In addition to volcanic quakes, fumarolic gas was confirmed in December and areas with increased ground heat have been expanding.
Mount Io is known to have erupted periodically between 1500 and 1700, the agency said.