The Japan Meteorological Agency warned Sunday of a possible small eruption at Mt. Io, which straddles the southwestern prefectures of Miyazaki and Kagoshima, after observing an increase in volcanic earthquakes. The local government in Ebino city declared a 1-kilometer no-entry zone around the crater of Mt. Io, part of the Kirishima mountains. Volcanic activity has intensified at the 1,317-meter volcano since last year. The agency said no visible signs of eruption or crustal movement have been observed, but there have been 37 volcanic temblors by midday Sunday.