Mount Semeru, located on the border of Lumajang and Malang regencies in East Java, showed significant volcanic activity again on Sunday (28/6/2026). The eruption, which occurred at 11:37 WIB, recorded an ash column spewing 1,000 meters above the peak, reaching 4,676 meters above sea level.
According to a report by Mount Semeru Observation Post officer Mukdas Sofian, the ash column was observed to be white to gray with a thick intensity, moving toward the southeast and south. This geological phenomenon was recorded with a maximum amplitude of 22 millimeters and a tremor duration of 170 seconds.
Throughout today, the highest mountain on the island of Java has been recorded to have erupted four times. The first activity began at 05:35 WIB, followed by a series of eruptions at 06:32 WIB and 09:11 WIB with varying intensities. This series of eruptions indicates that Semeru's volcanic activity is still in a fluctuating phase.
As of now, Mount Semeru's status remains at Level III (Alert). Volcanological authorities urge the public not to conduct any activities within a five-kilometer radius from the summit crater to avoid the risk of incandescent rocks, which pose a danger to public safety.
Additionally, people are advised to stay away from the southeastern sector along Besuk Kobokan up to 13 kilometers from the eruption center. Residents are also urged to increase vigilance against the threats of pyroclastic flows, lava, and cold lahar flows that could potentially flow along the riverbeds of Besuk Kobokan, Besuk Bang, Besuk Kembar, as well as nearby small tributaries.
