Mount Semeru, located on the border of Lumajang and Malang Regencies, East Java, showed a significant increase in volcanic activity on Wednesday (1/7/2026). Throughout the day, the highest volcano on Java Island was recorded erupting four times, with the highest ash column reaching 1 kilometer above the peak.
Based on data from the Mount Semeru Observation Post, the series of eruptions began early in the morning at 00:52 WIB with an ash ejection reaching a height of 700 meters. Activity continued into the morning, with peak eruptions occurring at 09:24 WIB and 10:10 WIB, spewing volcanic ash up to a height of 1 kilometer above the peak, or 4,676 meters above sea level.
So far, the Regional Disaster Management Agency (BPBD) of Lumajang stated that it has not received reports of any significant impact from the ash dispersion on residential areas. Nevertheless, Mount Semeru's status currently remains at Level III (Alert), so high vigilance is still required.
Chief Executive of BPBD Lumajang, Isnugroho, emphasized that the public must continue to comply with safe zone recommendations. Residents are prohibited from engaging in activities within a 5-kilometer radius of the crater and must stay away from the southeastern sector along Besuk Kobokan up to a distance of 13 kilometers from the peak.
Furthermore, local authorities urged the public to be aware of the threats of pyroclastic flows, lava, and cold lahar flows along riverbeds such as Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat. Residents are asked to maintain a safe distance of at least 500 meters from the riverbanks in these areas to anticipate potential follow-up volcanic hazards.
