A volcano in central Japan erupted on Saturday injuring at least eight people and forced aircraft to divert flying routes to void the billowing ash cloud.The Meteorological Agency said Mt. Ontake, which straddles Nagano and Gifu prefectures, erupted at around 11:53 a.m. (0253 GMT), sending smoke down the mountain's south slope for more than three kms (1.9 miles)."Seven people were lightly injured and one person suffered serious injuries as a result of the eruption," Makoto Hasegawa of the Nagano prefecture fire department told Reuters.The eruption is still taking place, he said."Airplanes are diverting their flying routes to avoid the ash cloud," said Hasegawa.NHK public broadcaster showed footage of the mountain sending thick, grey smoke into the air.Mt. Ontake is located some 200 km (125 miles) west of Tokyo. No nuclear power plants are located nearby.