Mount Semeru, located in East Java, showed significant volcanic activity again on Saturday morning (4/7/2026). At around 06:08 WIB, the highest volcano on the island of Java spewed a column of volcanic ash approximately 1,400 meters above its peak.
According to a report from the Center for Volcanology and Geological Hazard Mitigation (PVMBG), the observed ash column was white to gray in color with moderate intensity, drifting toward the south. The eruptive activity was recorded on a seismogram with a maximum amplitude of 22 millimeters and lasted for 2 minutes and 17 seconds.
Currently, Mount Semeru remains at Level III Status (Siaga/Alert). To minimize the risk of casualties, authorities have strictly prohibited the public from engaging in any activities in the southeastern sector along Besuk Kobokan, within a 13-kilometer radius from the eruption epicenter.
In addition, residents are prohibited from conducting activities within a 5-kilometer radius of the main crater due to the high threat of incandescent rock ejection. People are also advised to maintain a safe distance of 500 meters from the riverbanks along Besuk Kobokan, given the potential expansion of pyroclastic flows and cold lahar flows that could reach up to 17 kilometers from the summit.
PVMBG has urged residents living near rivers originating from Semeru's summit, such as Besuk Bang, Besuk Kembar, and Besuk Sat, to remain vigilant for potential lahar floods that could occur at any time. Intensive monitoring continues as the eruption was still ongoing when this report was released.
