Mount Mahameru Eruption in the Southeast Asian nation Triggers Evacuations

Indonesia's Mount Semeru, the tallest summit on the island of Java, has exploded, blanketing multiple communities with falling ash, prompting evacuations and leading authorities to raise the alert to the highest level.

The mountain in the province of East Java unleashed blistering plumes of hot ash and a mixture of stone, molten rock, and gases that travelled up to 7km down its sides multiple times from noon to dusk, while a thick column of fiery clouds rose 1.2 miles into the air, according to the nation's geological authority.

The outbursts that unfolded throughout the day forced officials to increase the volcano’s alert level on two occasions, from the third-highest level to the top level, the agency reported. No deaths or injuries have been reported.

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 stated that heightened volcanic movements of the volcano on the afternoon of Wednesday led officials to expand the hazard area to 8km from the summit. People were advised to keep away from an zone along the Kobokan River, which is the path of the lava flow, as searing gas flowed down Semeru’s slopes.

Videos on social media showed a thick plume of ash moving through a wooded ravine to a river beneath a bridge. Locals, some with faces smeared with volcanic dust and rain, escaped to makeshift refuges or departed for other safe areas.

Regional news outlets reported that authorities were facing challenges to save about 178 people trapped on the 3,676-metre mountain at the Ranu Kumbolo monitoring post. The party comprised 137 hikers, 15 porters, seven escorts and six tourism officials, according to an spokesperson with the protected area.

“They remain secure at Ranu Kumbolo monitoring post,” an official said in a recorded message. He noted the station was located 2.8 miles from the summit on the northern slope of the volcano, which is outside the trajectory of the hot cloud flow that was observed traveling to the southeast direction. Bad weather and rain forced the team to remain overnight there, he explained.

Semeru, also known as Mahameru, has erupted numerous times in the past 200 years. Still, as is the situation with many of the 129 active volcanoes in the archipelago, thousands of residents continue 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 villages were submerged in layers of mud. The eruption forced the relocation of more than 10,000 residents from their houses.

The country, an archipelago of more than 280 million inhabitants, is located along the Pacific “ring of fire”, a horseshoe-shaped series of fault lines, and is prone to seismic events and volcanism.