Four Indonesian Volcanoes Erupt Simultaneously, Ash Clouds Spread Widely

Four volcanoes in Indonesia erupted concurrently on Sunday morning, September 6, 2026. As of 9:00 AM Western Indonesia Time (WIB), Anak Krakatau, Ibu, Ili Lewotolok, and Semeru mountains have all registered eruptions. The affected volcanoes are geographically dispersed: Anak Krakatau in the Sunda Strait, Semeru in East Java, Ili Lewotolok in East Nusa Tenggara, and Ibu in West Halmahera. Anak Krakatau has been erupting since Friday night, September 4, with its volcanic ash reportedly spreading from Bengkulu to Jakarta. The Geological Agency of the Ministry of Energy and Mineral Resources reported an eruption at 7:10 AM WIB, recorded with a maximum amplitude of 50 mm and a duration of 16 seconds. The Meteorology, Climatology, and Geophysics Agency (BMKG) analyzed that the ash cloud from Anak Krakatau is splitting into two directions, with one part affecting parts of DKI Jakarta, Banten, and West Java, as well as surrounding waters. The second part is moving southwest-northwest, covering parts of Banten, Lampung, Bengkulu, the southern part of the Sunda Strait, and the Indian Ocean west of Bengkulu-Lampung-Banten. Mount Ibu in North Maluku also erupted on Sunday. The Geological Agency noted a volcanic ash column of approximately 400 meters above the peak (around 1,725 meters above sea level), with a moderate intensity gray ash cloud moving northeast. This eruption was recorded with a maximum amplitude of 15 mm and a duration of 35 seconds, according to the agency's release on Sunday. Mount Ili Lewotolok in Lembata Regency, East Nusa Tenggara, has experienced a series of eruptions in the last 48 hours. The strongest eruption occurred at 6:41 AM Central Indonesia Time (WITA) on Sunday, with an ash column observed at 600 meters above the peak (equivalent to 2,023 meters above sea level). The thick gray ash cloud was observed moving southeast and was recorded with a maximum amplitude of 40 mm and a duration of 82 seconds. Mount Semeru in East Java erupted at 7:51 AM WIB on Sunday. The observed ash column reached approximately 1,000 meters above the peak. Based on reports from the Geological Agency, this eruption was recorded with a maximum amplitude of 23 millimeters and a duration of 102 seconds. The agency has advised the public to avoid any activity in the southeastern sector along the Besuk Kobokan river, within 13 km of the summit (center of eruption). Beyond this distance, residents are warned to stay at least 500 meters away from the riverbanks along Besuk Kobokan due to the potential for hot clouds and lahar flows extending up to 17 km from the summit. Source: CNN Indonesia