Mount Anak Krakatau erupted overnight into Saturday, September 5, 2026, sending incandescent rocks and volcanic ash into the atmosphere above the Sunda Strait, according to Indonesia’s Geological Agency. The ongoing activity follows a status upgrade to Alert Level III, which officials instituted on July 2 after heightened seismic signals from the volcano located between the islands of Java and Sumatra.
Volcanic Activity and Eruption Timeline
According to data from the MAGMA Indonesia website cited by the Geological Agency, continuous eruptions accompanied by loud rumbling sounds began late Friday evening. Berton Panjaitan, acting head of the Disaster Data, Information and Communication Centre at the National Disaster Mitigation Agency (BNPB), stated that the eruption kicked off at 11:07 p.m. local time on Friday, September 4, 2026. Seismographs recorded an eruption earthquake with an amplitude of 70mm and a duration of 21,600 seconds between midnight and 6:00 a.m. on Saturday.
The Geological Agency reported that the nighttime activity resembled a “lava fountain” that produced active lava flows. Observers at the Krakatau Pasauran PGA Post noted that while the exact height of the eruption column could not be measured directly due to darkness, a bright red eruption plume and glowing material were clearly visible. The active phase also damaged field surveillance equipment, with a monitoring camera knocked out after being struck by ejected volcanic material, according to BNPB.
Public Safety and Tsunami Assessments
Authorities have maintained a mandatory 3-kilometer exclusion zone around the active crater of Anak Krakatau, urging residents and tourists not to approach the area for photography or observation. The Center for Volcanology and Geological Hazard Mitigation (PVMBG) addressed widespread public anxiety across coastal areas of Banten and Lampung, particularly regarding fears of a repeat of the destructive December 22, 2018 tsunami. Government assessments indicate that the regrown body of Anak Krakatau remains relatively small, meaning there is no current potential for a structural collapse large enough to trigger a tsunami.
Residents across West Java, Banten, and Lampung reported hearing booming sounds and feeling ground vibrations that coincided with the late-night eruptions. Despite the startling noises and light ashfall recorded along parts of the Banten coast, BNPB urged the public to remain calm while monitoring official updates from disaster mitigation teams.
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