Mount Semeru Eruption in Indonesia Prompts Evacuations

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

The mountain in the province of East Java released searing clouds of hot ash and a mixture of stone, molten rock, and gases that travelled up to 4 miles down its slopes several times from midday to dusk, while a dense plume of hot clouds rose 2km into the air, according to Indonesia’s Geology Agency.

The eruptions that occurred throughout the day forced authorities to raise the mountain's warning status twice, from the level three to the top level, the authority said. No casualties have been reported.

More than 300 inhabitants in the three communities most at risk in the area of Lumajang were evacuated to government shelters, according to a spokesperson for the national disaster mitigation agency.

He stated that heightened volcanic movements of the volcano on the afternoon of Wednesday prompted authorities to widen the danger zone to 8km from the crater. Residents were urged to keep away from an zone along the Besuk Kobokan River, which is the path of the molten rock stream, as scorching gases flowed down Semeru’s slopes.

Footage on social media displayed a dense cloud of ash moving through a wooded ravine to a waterway beneath a overpass. Residents, some with faces smeared with volcanic dust and rain, fled to makeshift refuges or left for other safe areas.

Local media reported that emergency teams were facing challenges to save about 178 individuals stranded on the 3,676-metre peak at the Ranu Kumbolo observation station. The party comprised 137 hikers, 15 porters, seven guides and six tourism officials, according to an spokesperson with the protected area.

“They are currently safe at Ranu Kumbolo monitoring post,” an official said in a recorded message. He said the station was located 4.5km from the crater on the north side of the volcano, which is outside the trajectory of the fiery cloud movement that was observed moving to the southeast direction. Bad weather and precipitation forced the group to spend the night there, he explained.

The volcano, also known as Great Mountain, has burst numerous times in the last two centuries. Still, as is the case with many of the 129 active volcanoes in the archipelago, thousands of people continue to reside on its productive highlands.

Semeru’s last major eruption was in December 2021, when 51 people were lost their lives and several hundred others were burned and settlements were buried in layers of mud. The eruption forced the relocation of over ten thousand residents from their houses.

The country, an island chain of over 280 million inhabitants, is located along the Pacific “ring of fire”, a curved series of fault lines, and is prone to seismic events and volcanic activity.