Volcano Semeru Outburst in Indonesia Prompts Evacuations

The nation's Mount Semeru, the tallest summit on Java island, has exploded, covering multiple communities with falling ash, prompting evacuations and leading authorities to raise the warning to the maximum level.

The volcano in East Java province unleashed searing clouds of hot ash and a mixture of stone, molten rock, and gases that travelled up to 7km down its slopes several times from midday to evening, while a dense plume of fiery clouds rose 2km into the air, according to Indonesia’s Geology Agency.

The eruptions that occurred throughout the day compelled authorities to raise the mountain's warning status twice, from the third-highest level to the top level, the authority reported. No casualties have been announced.

Over three hundred residents in the three communities most endangered in the district of Lumajang region were evacuated to official safe havens, according to a spokesperson for the national disaster mitigation agency.

He said that heightened volcanic movements of the volcano on the afternoon of Wednesday prompted officials to expand the danger zone to 5 miles from the summit. People were urged to stay clear from an area along the Kobokan River, which is the route of the molten rock stream, as searing gas moved down the volcano's sides.

Footage on online platforms displayed a thick plume of ash moving through a wooded ravine to a river beneath a overpass. Locals, some with faces covered with volcanic dust and water, fled to makeshift refuges or departed for other safe areas.

Local media reported that emergency teams were facing challenges to save about 178 people trapped on the 3,676-metre mountain at the Ranu Kumbolo monitoring post. The group included 137 hikers, 15 porters, seven guides and six tourism officials, according to an official with the national park.

“They are currently safe at Ranu Kumbolo monitoring post,” an official said in a video statement. He said the station was located 2.8 miles from the crater 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. Inclement conditions and precipitation forced the group to remain overnight there, he explained.

Semeru, also called Mahameru, has burst many occasions in the last two centuries. However, 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 people were lost their lives and several hundred others were burned and settlements were submerged in thick mud. The eruption led to the relocation of more than 10,000 residents from their houses.

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