Mount Mahameru Eruption in Indonesia Prompts Emergency Relocations

Indonesia's Mount Semeru, the tallest summit on Java island, has erupted, covering multiple communities with falling ash, prompting evacuations and causing officials to elevate the warning to the highest level.

The volcano in East Java province unleashed blistering plumes of fiery ash and a mixture of stone, molten rock, and gases that travelled up to 4 miles down its slopes several times from noon to evening, while a thick column of hot clouds rose 2km into the sky, according to the nation's geological authority.

The outbursts that occurred throughout the day compelled officials to increase the volcano’s alert level on two occasions, from the level three to the highest, the authority reported. No deaths or injuries have been reported.

Over three hundred residents in the three villages most at risk in the district of Lumajang region were evacuated to government shelters, as mentioned by a representative for the national disaster mitigation agency.

He said that heightened volcanic movements of the mountain on the afternoon of Wednesday prompted officials to widen the danger zone to 8km from the crater. Residents were advised to stay clear from an area along the Kobokan River, which is the route of the lava flow, as searing gas flowed down Semeru’s slopes.

Footage on online platforms displayed a thick plume of volcanic dust sweeping through a forested valley to a river beneath a bridge. Locals, some with faces smeared with volcanic dust and water, fled to temporary shelters or departed for other safe areas.

Local media indicated that authorities were facing challenges to rescue about 178 individuals trapped on the 3,676-metre mountain at the Ranu Kumbolo monitoring post. The party comprised 137 hikers, 15 porters, seven guides and six travel representatives, according to an official with the protected area.

“They remain secure at Ranu Kumbolo monitoring post,” a spokesperson said in a video statement. He noted the post was situated 4.5km from the summit on the northern slope of the volcano, which is not in the path of the hot cloud flow that was observed traveling to the south-southeast. Inclement conditions and rain forced the team to remain overnight there, he explained.

Semeru, also known as Mahameru, has burst many occasions in the last two centuries. However, as is the case with many of the 129 live volcanoes in the archipelago, thousands of people still to live on its fertile slopes.

Semeru’s previous significant explosion was in December 2021, when 51 individuals were killed and hundreds more were injured and settlements were submerged in layers of mud. The event forced the relocation of over ten thousand residents from their houses.

The country, an island chain of more than 280 million inhabitants, sits along the Pacific “ring of fire”, a curved series of tectonic boundaries, and is susceptible to earthquakes and volcanic activity.