Indonesia raises Anak Krakatau volcano status to Alert

Indonesia's Geological Agency has elevated the status of the Anak Krakatau volcano to "Alert" (Level III) starting July 2, 2026, citing a comprehensive analysis of its activity. This upgrade from "Watch" (Level II) reflects a notable increase in the volcano's unrest.

A 3-kilometer radius around the volcano's center has been designated as a danger zone. The agency has warned the public, including tourists and climbers, to stay clear of this area. Residents are urged to remain vigilant against potential threats such as pyroclastic flows, lava, hot rock fragments, and heavy ashfall.

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Based on the results of comprehensive analysis and evaluation, the activity level of Anak Krakatau Volcano has been raised from Level II (Watch) to Level III (Alert) effective from July 2, 2026, at 4:30 PM Western Indonesian Time.

Monitoring data since June 1, 2026, revealed the presence of SO2 emissions and heat anomalies, with a thermal anomaly detected in the crater on June 10. These signs were accompanied by high-intensity smoke emissions from the crater and a significant surge in shallow volcanic earthquakes, including "emissions," "hybrid," and "low frequency" types. For instance, between June 18-19, the daily occurrence of these shallow earthquakes exceeded 50.

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Residents around Anak Krakatau and visitors/tourists/climbers are not allowed to enter and conduct activities within a 3-kilometer radius of the center of Anak Krakatau's activity and must increase their vigilance against the threat of pyroclastic clouds, lava, and hot rock fragments, as well as heavy ashfall.

While deep volcanic earthquakes have not increased, the rise in shallow seismic activity suggests magma is actively moving near the surface. Between June 16 and July 2, the agency recorded hundreds of various seismic events, including over 740 "emissions" earthquakes and 520 "hybrid" events. Tiltmeter data indicates fluctuating but generally stable ground deformation, with some signs of low-level inflation.

Most recently, on July 2, an eruption occurred, sending an ash column approximately 200 meters above the summit. This eruption was detected by the Volcanic Ash Advisory Centre in Darwin, Australia. The volcano's real-time seismic amplitude measurements have shown a low-energy fluctuation but a recent tendency towards a slight increase.

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Although not accompanied by an increase in volcanic earthquakes associated with deep volcanic tremors (Volcanic A and Volcanic B) and deformation, the increase in earthquakes associated with shallow volcanic tremors indicates magma dynamics of Anak Krakatau Volcano at the surface.