Mount Semeru Erupts Multiple Times, Remains at Level III Alert in East Java

Mount Semeru Continues Activity with Multiple Eruptions

Mount Semeru, located in East Java, Indonesia, erupted multiple times on Thursday, February 26, 2026, with its activity level consistently maintained at Level III (Alert). The Center for Volcanology and Geological Hazard Mitigation (PVMBG) reported significant volcanic activity throughout the day, including ash emissions and seismic events. This marks a continuation of frequent eruptions, with the volcano recording 20 to 21 eruptions in the past week alone.

Details of February 26 Volcanic Activity

On Thursday, February 26, 2026, Mount Semeru experienced several notable eruptions. One eruption occurred at 08:23 WIB, producing an ash column that reached approximately 500 meters above the peak, or 4,176 meters above sea level. The ash column was described as white to gray with thick intensity, drifting towards the northeast. This event was recorded on the seismograph with a maximum amplitude of 22 millimeters and a duration of 110 seconds. Later that evening, another eruption was reported at 10:12 PM WIB, with seismic data showing a maximum amplitude of 21 millimeters and a duration of 118 seconds, though no visual observation of the ash column was recorded due to conditions.

Beyond explosive eruptions, heavy rainfall on Thursday triggered a significant cold lava flood (lahar) that lasted for nearly four hours in the early morning. The flood vibration, recorded with an amplitude of 17 mm and a duration of 13,304 seconds, was caused by rain carrying loose volcanic materials down the volcano's slopes. While the flow reportedly remained contained within river channels, it prompted heightened alert among disaster officials.

Official Warnings and Exclusion Zones Remain in Effect

In response to the ongoing volcanic activity, the PVMBG has reiterated strict warnings and established exclusion zones to ensure public safety. Residents and visitors are advised against any activities within the southeast sector along Besuk Kobokan, extending up to 13 kilometers from the peak (eruption center). Furthermore, a 500-meter buffer zone from the riverbanks along Besuk Kobokan is mandatory due to the potential for expanding hot clouds and lahar flows, which could reach up to 17 kilometers from the peak. People are also prohibited from conducting activities within a 5-kilometer radius of the crater or summit due to the risk of incandescent rock ejections.

Continuous Monitoring of Indonesia's Most Active Volcano

Mount Semeru, known as the highest volcano on Java Island, is one of Indonesia's most active volcanoes and is under continuous monitoring by the PVMBG. The volcano's persistent activity underscores the volatile nature of the region, which sits on the Pacific 'Ring of Fire'. Throughout 2026, MAGMA Indonesia has recorded a total of 778 volcanic eruptions across the country, with Mount Semeru accounting for the highest number at 405 events. Authorities remain vigilant, conducting seismic observations and visual monitoring to assess potential hazards and provide timely updates to the public.