Mount Ontake erupted late Saturday morning , sending a plume of smoke and ash into the sky , the Japan Meteorological Agency reported . At least three people have been injured , said a task force in Otaki village , just south of the volcano . They have observed 17-20 inches ( 40-50 centimeters ) of volcanic ash covering the ground . Local authorities said there were roughly 150 hikers in the area at the time , according to the agency , which raised the Volcanic Alert Level for Ontake from 1 to 3 . 'Volcanic unrest ' shakes California . The public is advised to not approach the volcano , and police and firefighters have deployed to help hikers near the summit . About 250 people living near the mountain have decided to remain in their homes , police said . The volcano last erupted in 2007 . It is located about 155 miles ( 250 kilometers ) west of Tokyo . 10 of the world 's most photogenic volcanoes .
A nearby village task force reports 16-20 inches of ash on the ground . Local authorities say there were about 150 hikers in the area when Ontake erupted . The Volcanic Alert Level has been raised from 1 to 3 . Comment: