Anak Krakatau shows renewed activity, alert raised to Level III

Indonesia's Anak Krakatau volcano has exhibited recent heightened activity, leading to an increase in its alert level to Level III, the second-highest designation in the nation's four-tier volcanic alert framework. The country's Geological Agency announced the escalation from Level II on Friday evening. This assessment was based on observations of volcanic activity since early October 2026.

The agency noted that while there was a modest rise in seismic activity, it did not signify a substantial overall surge in volcanic tremors.

Anak Krakatau, situated in the Sunda Strait between Java and Sumatra, was downgraded to Level II on September 21 after a decrease in volcanic activity following a series of significant eruptions in early September. The latter activity produced volcanic ash that ascended into the atmosphere, resulting in the temporary suspension of over 2,961 flights and affecting approximately 341,000 passengers.

Friday's documented eruptions comprised one at 4:17 p.m. that emitted an ash column 250 meters above the summit, followed by another at 4:30 p.m. with a 150-meter column. Eleven additional eruptions were recorded between 6:28 p.m. and 9:20 p.m., although their ash columns were not visible. Of these, 26 were reported by the Volcanology and Geological Hazard Mitigation Centre's (PVMBG) full-day seismic monitoring.

The day also recorded at least five eruptions earlier in the month, spanning from October 5 to October 8, raising the total documented eruptions to 18 since the start of the month.

The Geological Agency reported sulphur dioxide emissions ranging from 71 to 237.5 tonnes per day between September 21 and October 9. They also observed incandescence at the volcano since October 6. Meanwhile, Australia's Darwin Volcanic Ash Advisory Centre (VAAC) reported that volcanic ash reached an altitude of around 1.8 kilometers above sea level at 10:50 p.m. on Friday, drifting westward over the Sunda Strait towards the Indian Ocean at approximately nine kilometers per hour before being anticipated to disperse within six to 12 hours.

The Geological Agency cautioned residents, visitors, and tourists about volcanic rocks, heavy ashfall, lava flows, and secondary eruptions, and prohibited entry within a five-kilometer radius of the eruption center and areas within a one-kilometer radius of two newly formed islands located northwest and southeast of Anak Krakatau.

They also advised coastal communities in Banten and Lampung provinces to remain calm, avoid spreading unverified tsunami rumors, and adhere to official safety instructions.