Volcanic activity at Mount Semeru showed a significant increase again on Monday (6/29/2026). The highest mountain on Java Island erupted, spewing a column of ash 1.2 kilometers high above the peak, equivalent to 4,876 meters above sea level (masl), accompanied by moderate rumblings.
According to reports from the Mount Semeru Observation Post, the eruption occurred at 16:39 WIB and was recorded on a seismograph with a maximum amplitude of 22 millimeters, lasting approximately 2 minutes and 9 seconds. The observed ash column was white to gray in color with thick intensity, moving toward the northeast and east sectors.
As of Monday evening, the volcano was recorded to have erupted nine times throughout the day. Given this series of activities, volcanology authorities have maintained Mount Semeru at Status Level III or Alert (Siaga).
In response to the situation, the Regional Disaster Management Agency (BPBD) of Lumajang has alerted personnel at the Curahkobokan Post and Oro-oro Ombo Post to monitor current conditions. Although there has been no direct impact on residential areas yet, the public is urged to strictly adhere to safety recommendations.
The Center for Volcanology and Geological Hazard Mitigation (PVMBG) prohibits residents from conducting activities within a five-kilometer radius of the crater. Additionally, residents are forbidden from engaging in any activities in the southeastern sector along Besuk Kobokan within a 13-kilometer radius from the eruption center, and must remain vigilant against the threat of pyroclastic flows and lahars along river basins originating from the peak.
