Indonesia Says Anak Krakatau's 25-Hour Continuous Eruption Has Ended

Indonesia Says Anak Krakatau’s 25-Hour Continuous Eruption Has Ended

Reporter

September 7, 2026 | 10:21 am

TEMPO.CO, Jakarta - Indonesia’s Geological Agency of the Ministry of Energy and Mineral Resources (ESDM) has reported that the episode of continuous eruption at Mount Anak Krakatau in the Sunda Strait has concluded after lasting 25 hours.

Lana Saria, Head of the Geological Agency, stated in an evaluation report on Mount Anak Krakatau’s activity—received in Jakarta on Monday—that the continuous eruption episode, which began on Friday (Sept 4) at 23:07 WIB, officially ended on Sunday (Sept 6) at 00:04 WIB.

“Following the end of that episode, Mount Anak Krakatau’s volcanic activity has transitioned back to Strombolian eruption characteristics, marked by the recording of three Strombolian-type eruption earthquakes,” Lana said.

The Geological Agency interprets this return to Strombolian eruptions as an indication that the prolonged phase of continuous eruption has ended. Nevertheless, the probability of subsequent eruptions in the near future remains high.

Based on instrumental observations from September 6–7, 2026, the Geological Agency recorded three eruption earthquakes, nine emission earthquakes, 93 low-frequency earthquakes, 98 hybrid/multi-phase earthquakes, four continuous tremor episodes, and one shallow volcanic earthquake.

The RSAM (Real-time Seismic Amplitude Measurement) graph, which had spiked on September 5, 2026, has shown a downward trend since September 6, 2026.

Meanwhile, tiltmeter deformation data from the Tanjung Station indicates slight inflation since early August 2026, while the Lava93 Station shows a constant pattern.

Based on this comprehensive evaluation, the Geological Agency maintains Mount Anak Krakatau’s activity status at Level III (Alert/Siaga).

Lana stated that the agency advises the public, tourists, and hikers against approaching or engaging in activities within a three-kilometer danger radius of the active crater to avoid threats such as incandescent rock ejections, pyroclastic flows, lava flows, and heavy ashfall. In addition, coastal residents in Banten and Lampung provinces are urged to remain calm and disregard rumors regarding a potential tsunami caused by the eruption; they are also advised to wear masks during outdoor activities to prevent respiratory issues resulting from exposure to volcanic ash.

Read: Which 5 Indonesian Volcanoes Are Showing Increased Activity? Anak Krakatau Among Them

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