Mount Mahameru Outburst in Indonesia Prompts Evacuations

Indonesia's Mount Semeru, the highest peak on Java island, has exploded, blanketing multiple communities with volcanic ash, prompting evacuations and causing officials to elevate the warning to the maximum level.

The volcano in the province of East Java released blistering plumes of hot ash and a mixture of rock, lava and gas that moved up to 4 miles down its sides several times from midday to evening, while a thick column of fiery clouds rose 2km into the air, according to Indonesia’s Geology Agency.

The outbursts that unfolded throughout the day forced authorities to increase the volcano’s alert level twice, from the level three to the top level, the agency reported. No casualties have been announced.

More than 300 residents in the three communities most at risk in the district of Lumajang region were evacuated to government shelters, as mentioned by a representative for the national emergency management body.

He said that increased activity of the mountain on Wednesday afternoon led authorities to expand the danger zone to 5 miles from the summit. People were advised to stay clear from an area along the Besuk Kobokan River, which is the route of the lava flow, as searing gas flowed down the volcano's sides.

Footage on online platforms displayed a dense cloud of volcanic dust sweeping through a wooded ravine to a river beneath a bridge. Residents, some with faces smeared with ash and water, escaped to makeshift refuges or departed for other safe areas.

Regional news outlets reported that authorities were struggling to save about 178 people stranded on the 12,060-foot peak at the Ranu Kumbolo monitoring post. The group comprised 137 hikers, 15 carriers, seven escorts and six tourism officials, according to an spokesperson with the protected area.

“They remain secure at Ranu Kumbolo monitoring post,” an official stated in a recorded message. He said the station was situated 4.5km from the summit on the north side of the mountain, which is outside the trajectory of the hot cloud flow that was observed moving to the south-southeast. Inclement conditions and precipitation forced the team to spend the night there, he added.

Semeru, also known as Great Mountain, has erupted many occasions in the last two centuries. However, as is the situation with numerous of the 129 active volcanoes in the archipelago, thousands of residents still to reside on its fertile slopes.

Semeru’s last major eruption was in December 2021, when 51 people were killed and hundreds more were injured and villages were buried in thick mud. The eruption forced the relocation of over ten thousand people from their homes.

The country, an island chain of over 280 million people, is located along the Pacific “ring of fire”, a curved series of fault lines, and is susceptible to earthquakes and volcanism.