Mount Semeru Records 33 Eruptions in a Week, Remains at Alert Level III

Mount Semeru Continues High Activity with 33 Eruptions in a Week

Mount Semeru, located in East Java, Indonesia, experienced another eruption on Thursday evening, February 12, 2026, at 9:47 PM Western Indonesian Time (WIB). This event marks the 33rd eruption recorded at the volcano in the past week, underscoring its persistent high activity. The volcano's alert level remains at Level III (Alert), the second-highest in Indonesia's four-tier system.

Details of Recent Volcanic Activity

The eruption on Thursday evening was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 130 seconds, though visual observation of an ash column was not possible at that specific time. However, earlier on February 12, explosive activity was observed, with a volcanic ash plume rising to an estimated 15,000 feet (4,600 meters) altitude. On Wednesday, February 11, 2026, Mount Semeru had multiple eruptions, with ash columns reaching up to 1,000 meters above the summit. The Center for Volcanology and Geological Hazard Mitigation (PVMBG) reported that Mount Semeru has been the most active volcano in Indonesia throughout 2026, recording 300 eruptions so far this year.

Alert Level and Safety Recommendations

The consistent volcanic activity has kept Mount Semeru at Level III (Alert). In response, the PVMBG has issued critical safety recommendations for the public:

• Residents are advised to avoid any activities in the southeast sector along the Besuk Kobokan, within a 13-kilometer radius from the peak (eruption center).
• Beyond this 13-kilometer exclusion zone, people should refrain from activities within 500 meters of the riverbanks along Besuk Kobokan. This is due to the potential for the expansion of pyroclastic flows and lahar flows, which could extend up to 17 kilometers from the peak.

These measures are in place to mitigate risks from hot clouds and lava flows, which pose significant hazards to communities near the volcano.

Geological Context of Mount Semeru

Mount Semeru, standing at 3,676 meters above sea level, is the highest volcano on Java Island and one of Indonesia's most active. Indonesia is situated along the Pacific 'Ring of Fire', a region known for its frequent seismic activity and numerous active volcanoes, with over 120 active volcanoes across the archipelago. Disaster agencies continue to closely monitor Semeru's activity and provide ongoing updates to local communities regarding potential hazards.