Mount Mahameru Outburst in Indonesia Prompts Emergency Relocations

Indonesia's Mount Semeru, the tallest summit on Java island, has exploded, covering multiple communities with falling ash, leading to evacuations and causing officials to elevate the alert to the maximum level.

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

The eruptions that occurred throughout the day forced authorities to increase the volcano’s alert level on two occasions, from the level three to the highest, the authority said. No deaths or injuries have been announced.

Over three hundred inhabitants in the three communities most endangered in the district of Lumajang region were evacuated to government shelters, as mentioned by a spokesperson for the national emergency management body.

He said that increased activity of the mountain on Wednesday afternoon prompted authorities to expand the hazard area to 8km from the crater. Residents were urged to stay clear from an area along the Besuk Kobokan River, which is the route of the lava flow, as scorching gases moved down the volcano's sides.

Videos on social media displayed a thick plume of volcanic dust sweeping through a forested valley to a waterway beneath a bridge. Residents, some with faces smeared with volcanic dust and rain, fled to makeshift refuges or departed for alternative secure locations.

Local media indicated that authorities were struggling to rescue about 178 people trapped on the 12,060-foot mountain at the Ranu Kumbolo observation station. The party comprised 137 climbers, 15 porters, seven escorts and six travel representatives, according to an spokesperson with the national park.

“They are currently safe at Ranu Kumbolo monitoring post,” a spokesperson said in a recorded message. He said the post was situated 4.5km from the crater on the north side of the volcano, which is not in the path of the hot cloud flow that was observed traveling to the southeast direction. Bad weather and rain required the team to remain overnight there, he explained.

Semeru, also called Mahameru, has burst many occasions in the past 200 years. Still, as is the situation with numerous of the 129 active volcanoes in Indonesia, 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 killed and several hundred more were injured and settlements were buried in layers of mud. The event led to the relocation of over ten thousand residents from their houses.

The country, an archipelago of over 280 million inhabitants, sits along the Pacific seismic belt, a horseshoe-shaped series of fault lines, and is susceptible to earthquakes and volcanism.