Japan's Mount Aso Volcano Is Spewing Rocks

A volcano in southern Japan is spewing volcanic rocks indicating it could be heading towards an eruption.

If it blows, researchers in Japan say it will be the first time Mount Aso has erupted in 22 years.

Scientists from the Fukuoka regional weather observatory found the rocks on the mountain on Thursday.

The volcanic rocks, called scorias, may have been formed from magma.

A plume from the eruption reached 1,000 metres (3,280 feet) above the crater, disrupting local air travel and forcing people to change their travel plans.

One student, who was due to fly to Tokyo to take exams but had to change his plans, said: "I was originally going to go to Tokyo by plane, but now I need to leave early in the morning and get there by Shinkansen (high speed bullet train)."

Japan's Meteorological Agency has kept a Level 2 alert around the zone.

That means access to areas near the crater are restricted but there is no bar to being on the mountain itself.

The observatory said while eruptions at the current levels may continue, they do not expect increased activity from the volcano.