Mount Semeru, located in East Java, showed significant volcanic activity again on Monday (13/7/2026). According to a report from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the eruption occurred at 09:21 WIB with the height of the ash column reaching 900 meters above the peak.
The spewed ash material was observed to be white to gray in color with thick intensity. The plume was directed to the east and southeast. Seismograph records showed that this eruption had a maximum amplitude of 22 millimeters with a duration of 106 seconds.
To date, Mount Semeru remains at Level III (Alert). Volcanic activity data recorded that throughout Monday morning, specifically from 00:00 to 06:00 WIB, there were 18 eruption earthquakes, four avalanche earthquakes, and two harmonic earthquakes, indicating ongoing magma dynamics within the earth.
Authorities strongly urge the public not to conduct any activities in the southeastern sector along Besuk Kobokan, within a radius of 13 kilometers from the eruption center. In addition, residents are asked to stay away from the river bank area up to a distance of 500 meters, given the potential expansion of hot clouds and lahar flows that can reach up to 17 kilometers from the peak.
It is worth noting that Mount Semeru has become the most active volcano in Indonesia throughout 2026. Out of a total of 3,145 eruptions recorded across Indonesia by MAGMA Indonesia this year, Mount Semeru contributed the highest number with 1,390 eruptions.
