Mount Semeru, located in East Java, showed an increase in volcanic activity again on Saturday (4/7/2026) morning. At around 06:08 WIB, the highest volcano on Java Island was recorded spewing volcanic ash up to 1,400 meters above the crater peak.
According to a report from the Center for Volcanology and Geological Hazard Mitigation (PVMBG), the observed ash column was white to gray with moderate intensity. The eruption column was observed leaning towards the south. This eruptive activity was recorded on a seismogram with a maximum amplitude of 22 millimeters and a duration of approximately 2 minutes 17 seconds.
Currently, Mount Semeru remains at Level III (Alert) status. Authorities emphasized that the public should not engage in any activities in the southeastern sector along Besuk Kobokan, within a 13-kilometer radius from the eruption center. A similar prohibition applies within a 500-meter radius from the riverbanks along Besuk Kobokan, given the risk of expanding pyroclastic flows and lahar flows that could reach up to 17 kilometers.
In addition to river flow risks, PVMBG also prohibits residents from approaching within a 5-kilometer radius of the main crater due to the danger of incandescent rock projectiles. The public is advised to remain vigilant against the threat of lava avalanches and potential lahars along river courses originating from the summit, such as Besuk Bang, Besuk Kembar, and Besuk Sat.
