Volcano Mahameru Eruption in Indonesia Prompts Emergency Relocations

The nation's Semeru volcano, the tallest summit on the island of Java, has exploded, blanketing multiple communities with falling ash, leading to evacuations and leading authorities to raise the alert to the maximum level.

The mountain in the province of East Java unleashed blistering plumes of fiery ash and a mixture of rock, lava and gas that moved up to 7km down its slopes multiple times from noon to dusk, while a thick column of hot clouds rose 2km into the sky, according to the nation's geological authority.

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

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

He said that heightened volcanic movements of the mountain on the afternoon of Wednesday led officials to expand the hazard area to 5 miles from the summit. Residents were advised to keep away from an zone along the Besuk Kobokan River, which is the route of the lava flow, as scorching gases moved down Semeru’s slopes.

Videos on social media showed a dense cloud of ash sweeping through a forested valley to a waterway beneath a bridge. Residents, some with faces smeared with ash and rain, escaped to temporary shelters or left for alternative secure locations.

Regional news outlets indicated that authorities were struggling to rescue about 178 people trapped on the 3,676-metre mountain at the Ranu Kumbolo monitoring post. The group included 137 hikers, 15 carriers, seven escorts and six travel representatives, according to an official with the national park.

“They remain secure at Ranu Kumbolo monitoring post,” an official stated in a recorded message. He said the post was located 2.8 miles from the crater on the north side of the mountain, which is not in the path of the hot cloud flow that was seen traveling to the south-southeast. Inclement conditions and rain forced the group to spend the night there, he added.

The volcano, also called Great Mountain, has burst many occasions in the past 200 years. However, as is the case with many of the 129 live volcanoes in the archipelago, thousands of residents still to live on its productive highlands.

Semeru’s previous significant explosion was in late 2021, when 51 people were killed and several hundred others were injured and settlements were buried in layers of mud. The eruption forced the relocation of more than 10,000 residents from their houses.

Indonesia, an archipelago of over 280 million people, is located along the Pacific seismic belt, a horseshoe-shaped series of tectonic boundaries, and is prone to earthquakes and volcanic activity.