Mount Mahameru Eruption in the Southeast Asian nation Triggers Emergency Relocations

Indonesia's Mount Semeru, the highest peak on the island of Java, has exploded, covering several villages with volcanic ash, prompting evacuations and leading authorities to raise the alert to the highest level.

The volcano in the province of East Java unleashed blistering plumes of hot ash and a combination of stone, molten rock, and gases that moved up to 7km down its slopes several times from midday to evening, while a thick column of hot clouds rose 1.2 miles into the sky, according to Indonesia’s Geology Agency.

The outbursts that unfolded throughout the day forced authorities to increase the volcano’s alert level twice, from the level three to the top level, the agency reported. No casualties have been reported.

More than 300 residents in the three villages most at risk in the area of Lumajang were relocated to official safe havens, according to a spokesperson for the national emergency management body.

He stated that increased activity of the mountain on the afternoon of Wednesday prompted authorities to widen the hazard area to 8km from the crater. 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 flowed down Semeru’s slopes.

Videos on social media showed a dense cloud of ash moving through a wooded ravine to a waterway beneath a bridge. Locals, some with faces covered with ash and water, fled to temporary shelters or departed for alternative secure locations.

Local media indicated that emergency teams were facing challenges to rescue about 178 individuals trapped on the 3,676-metre mountain at the Ranu Kumbolo monitoring post. The group included 137 hikers, 15 porters, seven guides and six tourism officials, 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 noted the station was situated 2.8 miles from the crater on the north side of the volcano, which is not in the path of the fiery cloud movement that was seen traveling to the south-southeast. Bad weather and precipitation required the group to remain overnight there, he added.

Semeru, also called Mahameru, has erupted numerous times in the last two centuries. However, as is the situation with many of the 129 active volcanoes in Indonesia, tens of thousands of people continue to reside on its fertile slopes.

The mountain's last major eruption was in December 2021, when 51 people were killed and hundreds more were burned and villages were buried in thick mud. The eruption led to the relocation of more than 10,000 residents from their houses.

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