Geological Agency: Continuous Eruption of Mount Anak Krakatau Has Ended, Three Volcanoes Still Erupting
The Geological Agency of the Ministry of Energy and Mineral Resources (ESDM) has recorded that the continuous eruption episode of Mount Anak Krakatau in the Sunda Strait has ended after lasting 25 hours.
Head of the Geological Agency Lana Saria, in an evaluation report on the development of Mount Anak Krakatau’s activity received in Jakarta on Monday (7 September 2026), stated that the continuous eruption episode, which began on Friday (4 September 2026) at 23.07 Western Indonesian Time, officially ended on Sunday (6 September 2026) at 00.04 Western Indonesian Time.
“Following the end of the episode, the volcanic activity of Mount Anak Krakatau has transitioned back to strombolian eruption characteristics, marked by the recording of three strombolian eruption earthquakes,” said Lana.
The Geological Agency interprets the return of strombolian eruptions as a sign that the long-duration continuous eruption phase has ended. Nevertheless, the probability of follow-up eruptions in the subsequent period is still considered high.
Based on instrumental observations from 6 to 7 September 2026, the Geological Agency recorded three eruption earthquakes, nine blowing earthquakes, 93 low-frequency earthquakes, 98 hybrid or multi-phase earthquakes, four continuous tremor earthquakes, and one shallow volcanic earthquake.
The smoothed RSAM (Real-time Seismic Amplitude Measurement) chart, which spiked on 5 September 2026, now shows a declining trend since 6 September 2026. Meanwhile, tiltmeter deformation data from the Tanjung Station recorded indications of thin inflation since early August 2026, and the Lava93 Station shows a constant pattern.
Based on this comprehensive evaluation, the Geological Agency still sets Mount Anak Krakatau’s activity level at Level III (Alert).
According to Lana, the agency recommends that communities, tourists, and climbers do not approach or conduct activities within a three-kilometre danger radius of the active crater to avoid the threat of incandescent rock ejections, hot clouds, lava flows, and heavy ash rain.
In addition, coastal residents of Banten and Lampung provinces are urged to remain calm, not to believe hoaxes regarding the potential for a tsunami caused by the eruption, and are advised to wear masks when carrying out outdoor activities to anticipate respiratory problems from exposure to volcanic ash.