Mount Aso erupted Wednesday, spewing a giant column of ash thousands of meters into the sky as hikers rushed away from the popular tourist spot. No injuries were immediately reported after the late-morning eruption in Kumamoto Prefecture, which sent rocks flying in a dramatic blast captured by nearby CCTV cameras. People were warned not to approach the volcano as it ejected hot gas and ash as high as 3,500 meters, and sent stones tumbling down its grassy slopes.