Volcano Semeru Outburst in Indonesia Triggers Emergency Relocations

The nation's Semeru volcano, the highest peak on the island of Java, has erupted, covering several villages with falling ash, prompting evacuations and causing officials to elevate the warning to the highest level.

The mountain in East Java province released searing clouds of fiery ash and a combination of rock, lava and gas that travelled up to 7km down its slopes several times from noon to dusk, while a dense plume of hot clouds rose 1.2 miles into the air, according to Indonesia’s Geology Agency.

The outbursts that occurred throughout the day compelled authorities to raise the volcano’s alert level twice, from the level three to the top level, the authority reported. No casualties have been announced.

Over three hundred inhabitants in the three communities most at risk in the district of Lumajang region were evacuated to official safe havens, according to a representative for the national disaster mitigation agency.

He said that heightened volcanic movements of the mountain on Wednesday afternoon prompted authorities to expand the hazard area to 8km from the summit. Residents were advised to stay clear from an area along the Besuk Kobokan River, which is the route of the molten rock stream, as scorching gases flowed down the volcano's sides.

Videos on social media showed a thick plume of volcanic dust sweeping through a forested valley to a river beneath a bridge. Residents, some with faces smeared with volcanic dust and rain, escaped to temporary shelters or departed for alternative secure locations.

Regional news outlets indicated that authorities were facing challenges to rescue about 178 people trapped on the 3,676-metre mountain at the Ranu Kumbolo monitoring post. The party included 137 climbers, 15 carriers, seven guides and six travel representatives, according to an official with the national park.

“They remain secure at Ranu Kumbolo monitoring post,” a spokesperson said in a video statement. He said the station was located 4.5km from the summit on the north side of the mountain, which is not in the path of the fiery cloud movement that was observed moving to the south-southeast. Inclement conditions and rain forced the group to spend the night there, he explained.

Semeru, also known as Mahameru, has erupted numerous times in the last two centuries. However, as is the case with many of the 129 live volcanoes in the archipelago, tens of thousands of people continue to live on its fertile slopes.

Semeru’s previous significant explosion was in December 2021, when 51 people were lost their lives and hundreds others were burned and settlements were submerged in layers of mud. The eruption led to the evacuation of more than 10,000 people from their homes.

Indonesia, an archipelago of over 280 million people, sits along the Pacific “ring of fire”, a curved series of fault lines, and is prone to earthquakes and volcanic activity.