Indonesia’s Mount Semeru volcano erupted violently on Wednesday, unleashing massive ash clouds and fast-moving pyroclastic flows, prompting authorities to raise the alert to the highest level and initiate large-scale evacuations and rescues. The event has disrupted lives and highlighted the ongoing volcanic risks in one of the world’s most active regions.
The eruption began around midday and continued into the evening, with the volcano spewing a thick column of hot ash that rose approximately 2 kilometers into the air. Pyroclastic density currents—searing mixtures of rock, lava, and gas—traveled down the southern slopes, reaching distances of up to 13 kilometers in some areas. This intense activity forced Indonesia’s volcanology agency to escalate the alert level twice within hours, ultimately setting it at the maximum due to the high risk of further eruptions.
Authorities successfully rescued 178 individuals, including climbers, porters, guides, and tourism officials, who were stranded at the Ranu Kumbolo camping area on the northern slope. This site, located about 4.5 kilometers from the crater, was outside the immediate danger zone but exposed the group to volcanic ash. Bad weather had initially hampered rescue efforts, but all were brought to safety by Thursday, with no serious injuries reported among them.
In response to the eruption, nearly 1,000 residents from three villages in the Lumajang district were evacuated to government shelters. The national disaster mitigation agency coordinated the effort, focusing on areas within the expanded 8-kilometer danger zone from the crater. While no fatalities have been confirmed, local media reported several injuries, including two motorcyclists who suffered severe burns after crashing on a bridge covered in hot ash.
The eruption caused significant property damage in Lumajang, with homes and infrastructure buried under layers of volcanic ash. Videos shared on social media showed dense ash clouds sweeping through plantations and forested valleys, blocking sunlight and creating hazardous conditions. The ash fall prompted aviation warnings in Australia, highlighting the regional impact of the event and potential disruptions to air travel.
Mount Semeru, also known as Mahameru, is one of Indonesia’s most active volcanoes, with a history of eruptions over the past 200 years. Its last major event in December 2021 resulted in 51 deaths and forced the evacuation of over 10,000 people. Indonesia, situated on the Pacific ‘Ring of Fire,’ is prone to such volcanic activity, with 129 active volcanoes across the archipelago supporting millions of people living on fertile slopes.
Scientists monitoring the volcano noted ongoing high seismicity, with increasing signals of avalanches and continued eruption activity. Authorities have warned people to avoid the Besuk Kobokan River valley, which serves as a path for lava flows, and are considering further expanding the danger zone. The situation remains dynamic, with potential for additional eruptions in the coming days, requiring sustained vigilance.
The government’s swift response has mitigated immediate risks, but the eruption underscores the persistent volcanic threats in densely populated regions. Recovery efforts will focus on assessing damage, providing aid to evacuees, and monitoring Semeru’s activity to prevent future tragedies, emphasizing the need for robust disaster preparedness in vulnerable areas.
