Mount Mahameru Outburst in Indonesia Triggers Emergency Relocations

Indonesia's Semeru volcano, the highest peak on the island of Java, has exploded, blanketing multiple communities with volcanic ash, prompting evacuations and leading authorities to raise the alert to the maximum level.

The volcano in the province of East Java released searing clouds of hot ash and a mixture of rock, lava and gas that moved up to 4 miles down its slopes multiple times from midday to evening, while a thick column of fiery clouds rose 1.2 miles into the air, according to Indonesia’s Geology Agency.

The outbursts that unfolded throughout the day forced officials to increase the volcano’s alert level on two occasions, from the level three to the highest, the agency reported. No casualties have been reported.

Over three hundred inhabitants in the three villages most endangered 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 increased activity of the volcano on the afternoon of Wednesday led officials to expand the danger zone to 8km from the crater. Residents were advised to keep away from an area along the Kobokan River, which is the route of the lava flow, as searing gas flowed down the volcano's sides.

Footage on social media displayed a dense cloud of volcanic dust sweeping through a wooded ravine to a river beneath a overpass. Residents, some with faces covered with volcanic dust and rain, escaped to temporary shelters or departed for other safe areas.

Regional news outlets reported that emergency teams were struggling to rescue about 178 individuals trapped on the 3,676-metre mountain at the Ranu Kumbolo monitoring post. The group comprised 137 hikers, 15 porters, seven guides and six tourism officials, according to an spokesperson with the protected area.

“They are currently safe at the Ranu Kumbolo station,” a spokesperson stated in a video statement. He noted the post was situated 4.5km from the summit on the northern slope of the mountain, which is not in the path of the hot cloud flow that was observed moving to the southeast direction. Inclement conditions and precipitation required the team to spend the night there, he added.

Semeru, also known as Great Mountain, has erupted numerous times in the last two centuries. However, as is the case with many of the 129 active volcanoes in Indonesia, thousands of residents continue to reside on its fertile slopes.

Semeru’s last major eruption was in December 2021, when 51 people were killed and hundreds more were injured and settlements were submerged in layers of mud. The eruption forced the relocation of more than 10,000 people from their houses.

The country, an archipelago of over 280 million inhabitants, is located along the Pacific “ring of fire”, a curved series of fault lines, and is prone to earthquakes and volcanic activity.