Volcano Mahameru Outburst in Indonesia Prompts Evacuations

Indonesia's Semeru volcano, the tallest summit on Java island, has exploded, blanketing multiple communities with falling ash, leading to 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 stone, molten rock, and gases that travelled up to 7km down its slopes multiple times from noon to dusk, while a dense plume of fiery clouds rose 2km into the air, according to the nation's geological authority.

The outbursts that unfolded throughout the day forced officials to increase the mountain's warning status twice, from the level three to the highest, the authority said. No deaths or injuries have been announced.

Over three hundred residents in the three communities most at risk in the area of Lumajang region were relocated to government shelters, according to a spokesperson for the national emergency management body.

He said that increased activity of the mountain on the afternoon of Wednesday prompted officials to expand the danger zone to 5 miles from the summit. Residents were urged to stay clear from an zone along the Kobokan River, which is the path of the lava flow, as scorching gases flowed down the volcano's sides.

Videos on social media displayed a thick plume of volcanic dust sweeping through a wooded ravine to a river beneath a bridge. Residents, some with faces smeared with volcanic dust and rain, escaped to makeshift refuges or left for other safe areas.

Local media indicated that emergency teams were struggling to rescue about 178 people stranded on the 3,676-metre peak at the Ranu Kumbolo monitoring post. The party included 137 hikers, 15 carriers, seven escorts and six tourism officials, according to an official with the national park.

“They remain secure at the Ranu Kumbolo station,” a spokesperson said in a video statement. He noted the post was located 2.8 miles from the crater on the north side of the mountain, which is outside the trajectory of the fiery cloud movement that was seen traveling to the southeast direction. Bad weather and rain forced the group to spend the night there, he explained.

The volcano, also called Mahameru, has burst many occasions in the past 200 years. Still, as is the situation with many of the 129 live volcanoes in Indonesia, thousands of residents still to reside on its productive highlands.

Semeru’s previous significant explosion was in late 2021, when 51 people were lost their lives and hundreds others were injured and villages were submerged in thick mud. The eruption led to the relocation of more than 10,000 people from their houses.

The country, an archipelago of over 280 million people, sits along the Pacific seismic belt, a horseshoe-shaped series of tectonic boundaries, and is prone to seismic events and volcanism.