Mount Semeru, located in Lumajang Regency, East Java, showed a significant increase in volcanic activity once again in the early hours of Saturday (4/7/2026). This natural phenomenon was marked by a series of eruptions that ejected a gray ash column reaching a height of approximately 1,000 meters above the crater peak.
According to an official report from the Mount Semeru Observation Post officer, Liswanto, flows of incandescent material were observed sliding from the crater peak. The material was reported to be moving toward the southeastern sector, reaching a distance of 1,000 meters, heading towards the Besuk Kobokan flow area.
As of now, the status of Mount Semeru remains at Level III (Alert). Although there has been no change in status, relevant authorities emphasized that the volcanic activity of the highest mountain on Java Island is still considered high, meaning the threat of danger to communities on the slopes remains.
Relevant authorities have issued a strict warning advising the public not to conduct any activities within a 13-kilometer radius from the summit. Vigilance must be increased, particularly along the riverbeds originating from the mountain, to anticipate the risk of hot pyroclastic flows and cold lahar floods, which could be triggered by heavy rainfall in the summit area.
