Volcano Semeru Outburst in Indonesia Prompts Evacuations

Indonesia's Semeru volcano, 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 maximum level.

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

The outbursts that occurred throughout the day compelled authorities to raise the mountain's warning status twice, from the level three to the highest, the authority reported. No deaths or injuries have been reported.

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

He stated that heightened volcanic movements of the mountain on Wednesday afternoon led authorities to widen the danger zone to 8km from the summit. Residents were advised to stay clear from an zone along the Besuk Kobokan River, which is the path of the molten rock stream, as scorching gases moved down Semeru’s slopes.

Videos on online platforms showed a thick plume of ash sweeping through a forested valley to a waterway beneath a overpass. Residents, some with faces covered with volcanic dust and water, fled to makeshift refuges or left for other safe areas.

Local media indicated that emergency teams were struggling to save about 178 people trapped on the 3,676-metre mountain at the Ranu Kumbolo monitoring post. The group comprised 137 climbers, 15 carriers, seven escorts and six tourism officials, according to an spokesperson with the protected area.

“They remain secure at the Ranu Kumbolo station,” a spokesperson said in a video statement. He noted the station was situated 2.8 miles from the summit on the north side of the volcano, which is not in the path of the hot cloud flow that was seen moving to the southeast direction. Inclement conditions and rain required the team to remain overnight there, he added.

The volcano, also known as Mahameru, has erupted many occasions in the past 200 years. Still, as is the case with numerous of the 129 active volcanoes in Indonesia, tens of thousands of people still to live on its fertile slopes.

Semeru’s last major eruption was in December 2021, when 51 people were killed and several hundred more were injured and settlements were buried in layers of mud. The eruption forced the evacuation of over ten thousand people from their homes.

The country, an island chain of over 280 million people, is located along the Pacific seismic belt, a curved series of tectonic boundaries, and is prone to earthquakes and volcanic activity.