High-level eruption at Anak Krakatau ejects ash over 15 km (50 000 feet) a.s.l., Indonesia

A high-level eruption at Anak Krakatau, Indonesia, ejected volcanic ash up to 15 km (50 000 feet) above sea level at WIB on September 5, 2026 ( UTC on September 4). Darwin Volcanic Ash Advisory Center (VAAC) later tracked the ash moving west at approximately 74 km/h (46 mph), while a second layer to about 5.5 km (18 000 feet) extended south. SIGMETs were issued for the Jakarta and Melbourne flight information regions. Aktivitas gunung anak krakatau selama 24 jam sebelum CCTV mati total Rip buat CCTV yang sudah bekerja siang malam memantau aktivitas tersebut. Dan semoga erupsi gn anak krakatau segera menurun pic. twitter. com/H9rvs9r0X6 — Sumatera Adil & Federal (@indepenSumatera) September 4, 2026 Darwin VAAC recorded a rapid increase in reported ash altitude late on September 4. Advisory 2026/163 placed ash at FL070, equivalent to approximately 2 km (7 000 feet) above sea level (a. s. l), at WIB ( UTC). Advisory 2026/164 identified a high-level eruption to approximately 14 km (45 000 feet) a. s. l., at WIB ( UTC). Ten minutes later, Advisory 2026/165 noted ash at approximately 15 km (48 000 feet), moving west at about 93 km/h (58 mph). SEMBURAN MAGMA DARI GUNUNG ANAK KRAKATAU SEMAKIN BESAR WAK. https://t. co/yM5g4TLhoM pic. twitter. com/wGSXuJdowT — Sumatera Adil & Federal (@indepenSumatera) September 4, 2026 Darwin VAAC said the high-level emission was continuing and based the altitude estimate on an infrared cloud-top temperature of −68°C (−90.4°F). Ash movement and subsequent forecasts were based on Himawari-9 satellite imagery and consensus model guidance. Advisory 2026/167, issued at UTC, identified two ash layers in satellite imagery at WIB on September 5 ( UTC on September 4). Ash extending from the surface to 15 km (48 000 feet) was moving west at approximately 74 km/h (46 mph), while a second layer extending to about 5.5 km (18 000 feet), was moving south at approximately 19 km/h (12 mph). As of UTC on September 4, official sources had not reported airport closures, flight cancellations or delays. The South Lampung Regency Disaster Management Agency (BPBD), citing a September 3 evaluation ’s Ministry of Energy and Mineral Resources, reported that Anak Krakatau remained at Level III (Siaga). The evaluation described shallow or near-surface magma dynamics as very high and maintained a 3 km (1.9 miles) exclusion zone around the active crater. During the August 22–31 monitoring period, the Geological Agency recorded eruption columns rising 50–400 m (164–1 312 feet) above the crater. Sulfur dioxide emissions ranged from 715 to 2 922 tonnes (788–3 221 short tons) per day. The monitoring network recorded 174 eruption earthquakes, 714 emission events, 336 low-frequency earthquakes, 32 harmonic events, 851 hybrid or multiphase earthquakes and 30 periods of continuous tremor. BPBD said potential hazards identified in the September 3 evaluation included incandescent ejecta and heavy ashfall near the volcano.