Mount Mahameru Eruption in Indonesia Prompts Evacuations

The nation's Semeru volcano, the tallest summit on Java island, has erupted, covering several villages with volcanic ash, prompting evacuations and causing officials to elevate the alert to the highest level.

The volcano in the province of East Java unleashed searing clouds of hot ash and a combination of stone, molten rock, and gases that travelled up to 7km down its slopes multiple times from midday to dusk, while a thick column of hot clouds rose 1.2 miles 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 twice, from the level three to the top level, the authority said. No deaths or injuries have been announced.

More than 300 residents in the three communities most endangered in the area of Lumajang region were relocated to government shelters, according to a spokesperson for the national disaster mitigation agency.

He said that heightened volcanic movements of the mountain on Wednesday afternoon led authorities to expand the danger zone to 8km from the summit. People were urged to stay clear from an zone along the Kobokan River, which is the route of the lava flow, as searing gas flowed down Semeru’s slopes.

Videos on social media displayed a thick plume of ash sweeping through a wooded ravine to a river beneath a bridge. Locals, some with faces smeared with ash and water, escaped to temporary shelters or left for other safe areas.

Local media indicated that emergency teams were facing challenges to rescue about 178 people stranded on the 3,676-metre mountain at the Ranu Kumbolo monitoring post. The group comprised 137 climbers, 15 carriers, seven guides and six travel representatives, according to an spokesperson with the protected area.

“They remain secure at the Ranu Kumbolo station,” an official stated in a video statement. He noted the station was located 4.5km from the crater on the northern slope of the volcano, which is outside the trajectory of the hot cloud flow that was seen moving to the southeast direction. Bad weather and precipitation forced the group to spend the night there, he added.

Semeru, also known as Great Mountain, has erupted many occasions in the last two centuries. However, as is the situation with many of the 129 live volcanoes in the archipelago, tens of thousands of residents still to live on its fertile slopes.

Semeru’s last major eruption was in December 2021, when 51 people were lost their lives and hundreds more were injured and villages were submerged in thick mud. The eruption forced the relocation of over ten thousand people from their houses.

Indonesia, an island chain of over 280 million inhabitants, is located along the Pacific seismic belt, a curved series of fault lines, and is prone to seismic events and volcanic activity.