A cloud of black ash rushes towards the hikers.
Mount Aso erupted on Wednesday, October 20, causing rocks to twirl following a spectacular explosion filmed by CCTV cameras.
Authorities have warned locals and tourists not to approach the volcano, as hot gases and ash rise and stones roll down its green slopes.
No injuries were immediately reported but authorities are checking whether hikers may have been trapped, local officials told Japanese media, while footage showed dozens of vehicles and tour buses parked in the parking lot. 'a nearby museum offering an unobstructed view of the volcano.
To read also Eruption in the Canaries: "Many people have lost everything" because of the volcano
Culminating at 1,592 meters, Mount Aso is one of the most active volcanoes in the Japanese archipelago.
For those who are nearby, "you have to watch out for large boulders and flows of pyroclastic material," said Tomoaki Ozaki, an official with the Japan Meteorological Agency (JMA).
"Caution is called for, even in remote areas, because the wind can carry not only ashes but also stones," added Mr. Ozaki, also warning of possible toxic gases.
