TEMPO.CO, Jakarta - The highest volcano in Java, Mount Semeru, erupted again late Tuesday, April 7, 2026, spewing an ash column about 2,000 meters high above the summit, twice the height of the previous eruption on April 3.
Liswanto, an officer at the Semeru Volcano Observation Post (PGA) in Lumajang, East Java, reported that the ash column was heavily inclined towards the northeast and east. The eruption was recorded on the seismogram with a maximum amplitude of 27 mm and a duration of 7 minutes 23 seconds.
The eruption of Mount Semeru also emitted hot cloud. Liswanto stated in his report on Tuesday, April 7, 2026, "The Pyroclastic Flow (APG), with a sliding distance of 4,500 meters from the crater, is headed southeast (Besuk Kobokan)."
Isnugroho, the Acting Head of the Regional Disaster Mitigation Agency (BPBD) in Lumajang, confirmed the hot cloud, but said it did not affect the residents.
Mount Semeru's volcanic activity remains at alert Level III.
The Center for Volcanology and Geological Hazard Mitigation (PVMBG) issued several recommendations following the eruption. Residents are encouraged to avoid activities in the southeastern sector along Besuk Kobokan, up to 13 kilometers from the summit (eruption center).
Beyond this distance, surrounding communities should not engage in activities within 500 meters from the river edge along Besuk Kobokan due to the potential expansion of hot clouds and lava flow up to 17 kilometers from the peak. They should not be active within a 5-kilometer radius from the crater/peak of Mount Semeru due to the risk of projectile eruption materials.
Overall, residents are advised to be vigilant of the potential hot clouds, lava flows, and cold lava floods along the river/valley originating from the peak of Mount Semeru, especially along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, as well as the potential for lava floods on small rivers that are tributaries of Besuk Kobokan.
Read: Mount Semeru Erupts Twice This Morning, Alert Maintained at Level III