Volcano Mahameru Outburst in Indonesia Triggers Evacuations

Indonesia's Semeru volcano, the tallest summit on the island of Java, has exploded, covering multiple communities with falling ash, leading to evacuations and leading authorities to raise the warning to the highest level.

The volcano in East Java province unleashed searing clouds of hot ash and a combination of stone, molten rock, and gases that travelled up to 7km down its sides multiple times from noon to dusk, while a thick column of hot clouds rose 2km into the air, as stated by Indonesia’s Geology Agency.

The outbursts that unfolded throughout the day compelled authorities to raise the volcano’s alert level on two occasions, from the third-highest level to the highest, the agency reported. No casualties have been announced.

Over three hundred inhabitants in the three communities most at risk in the district of Lumajang region were relocated to official safe havens, as mentioned by a representative for the national emergency management body.

He stated that heightened volcanic movements of the mountain on Wednesday afternoon prompted officials to widen the danger zone to 8km from the crater. Residents were advised to stay clear from an zone along the Kobokan River, which is the route of the molten rock stream, as scorching gases flowed down Semeru’s slopes.

Footage on online platforms displayed a thick plume of ash sweeping through a wooded ravine to a waterway beneath a overpass. Residents, some with faces covered with ash and rain, escaped to temporary shelters or left for alternative secure locations.

Regional news outlets reported that authorities were facing challenges to save about 178 individuals trapped on the 12,060-foot peak at the Ranu Kumbolo monitoring post. The group comprised 137 climbers, 15 carriers, seven escorts and six travel representatives, according to an official with the protected area.

“They remain secure at the Ranu Kumbolo station,” an official said in a recorded message. He noted the station was located 2.8 miles from the summit on the north side of the mountain, which is outside the trajectory of the hot cloud flow that was seen traveling to the southeast direction. Bad weather and precipitation forced the group to remain overnight there, he added.

Semeru, also called Mahameru, has erupted numerous times in the past 200 years. Still, as is the situation with many of the 129 active volcanoes in the archipelago, thousands of people still to reside on its fertile slopes.

The mountain's last major eruption was in December 2021, when 51 people were lost their lives and hundreds others were injured and settlements were submerged in layers of mud. The eruption led to the evacuation of more than 10,000 people from their houses.

Indonesia, an archipelago of more than 280 million people, is located along the Pacific “ring of fire”, a curved series of fault lines, and is susceptible to earthquakes and volcanism.