Mount Semeru, located in East Java, showed a significant increase in volcanic activity again on Wednesday (1/7/2026). Throughout the day, the tallest mountain on Java Island was recorded to have erupted four times, with the highest ash column reaching 1 kilometer above the summit, which stands at 3,676 meters above sea level.
According to data from the Mount Semeru Observation Post, the series of eruptions began at 00:52 WIB with an ash column height of 700 meters. Activity continued at 08:14 WIB with an ash column of 800 meters. The intensity of the eruptions then increased at 09:24 WIB and 10:10 WIB, where the ash column reached a maximum height of 1 kilometer with thick intensity drifting toward the east, southeast, and south sectors.
The Chief Executive of Lumajang BPBD, Isnugroho, stated that as of now there have been no reports of significant impact from volcanic ash dispersion in residential areas. Nevertheless, he emphasized that Mount Semeru currently remains at Level III (Alert) status, so complete vigilance remains a priority.
Authorities have established an exclusion zone for public activity within a 5-kilometer radius from the crater center to avoid the danger of incandescent rock falls. In addition, residents are prohibited from engaging in activities in the southeast sector along Besuk Kobokan up to a 13-kilometer radius from the peak, as well as maintaining a minimum distance of 500 meters from the banks of rivers originating on the mountain to anticipate the threat of pyroclastic flows and cold lava flows.
Residents living along river basins, such as Besuk Bang, Besuk Kembar, and Besuk Sat, are urged to keep monitoring official information and heighten preparedness for potential lava flows and lahars that could occur at any time due to the volcanic activity.
