Volcano Semeru Eruption in Indonesia Triggers Evacuations

Indonesia's Mount Semeru, the highest peak on Java island, has erupted, blanketing several villages with falling ash, prompting evacuations and leading authorities to raise the warning to the maximum level.

The mountain in East Java province unleashed blistering plumes of hot ash and a mixture of stone, molten rock, and gases that travelled up to 4 miles down its slopes multiple times from midday to evening, while a dense plume of fiery clouds rose 1.2 miles into the air, as stated by Indonesia’s Geology Agency.

The outbursts that unfolded throughout the day compelled authorities to increase the volcano’s alert level on two occasions, from the level three to the top level, the agency reported. No deaths or injuries have been reported.

More than 300 residents in the three villages most at risk in the district of Lumajang region were evacuated to official safe havens, as mentioned by a representative for the national disaster mitigation agency.

He said that heightened volcanic movements of the volcano on the afternoon of Wednesday prompted officials to widen the danger zone to 5 miles from the summit. Residents were advised to keep away from an zone along the Kobokan River, which is the path of the lava flow, as searing gas moved down Semeru’s slopes.

Videos on social media displayed a dense cloud of ash moving through a wooded ravine to a waterway beneath a bridge. Residents, some with faces covered with volcanic dust and water, fled to makeshift refuges or departed for other safe areas.

Local media indicated that authorities were struggling to save about 178 individuals trapped on the 3,676-metre mountain at the Ranu Kumbolo observation station. The party included 137 hikers, 15 porters, seven escorts and six tourism officials, according to an official with the protected area.

“They remain secure at Ranu Kumbolo monitoring post,” a spokesperson stated in a recorded message. He said the post was located 4.5km from the crater on the northern slope of the mountain, which is outside the trajectory of the fiery cloud movement that was seen moving to the south-southeast. Inclement conditions and rain forced the team to remain overnight there, he added.

The volcano, also known as Mahameru, has erupted many occasions in the last two centuries. Still, as is the situation with many of the 129 active volcanoes in the archipelago, tens of thousands of residents continue to reside on its fertile slopes.

Semeru’s previous significant explosion was in late 2021, when 51 people were killed and several hundred more were burned and villages were submerged in thick mud. The event led to the evacuation of over ten thousand people from their houses.

Indonesia, an archipelago of more than 280 million people, sits along the Pacific “ring of fire”, a horseshoe-shaped series of tectonic boundaries, and is susceptible to seismic events and volcanic activity.