Indonesia's Anak Krakatau volcano keeps erupting, grounding hundreds of thousands of travelers

The eruption and its effects

Anak Krakatau ("child of Krakatoa"), located in the Sunda Strait between the islands of Java and Sumatra, has been erupting since the night of Friday, September 4. Two more eruptions occurred on Sunday morning, and the monitoring agency warned on Monday that the likelihood of further eruptions in the near term remains high.

According to Indonesia's meteorological agency BMKG, ash columns on the volcano's eastern side, toward Java, reached about 6,000 meters, while on the western side, toward Sumatra, they reached as high as 15,000 meters.

Airport closures and traveler numbers

Jakarta's Soekarno-Hatta International Airport was the first to close, on Sunday. According to the BBC, six airports were closed in total, affecting more than 150,000 passengers and around 467 flights. However, CNN Brasil reported that by Monday seven airports were closed, including two serving Jakarta, affecting around 341,000 travelers, with nearly 3,000 flights cancelled, diverted or delayed. Transport Minister Dudy Purwagandhi said the closures were extended to give airports time to clear runways, taxiways and aprons, and to allow airlines time to prepare their fleets. Flights to and from Singapore were hit hardest, along with routes to Doha, Sydney and Kuala Lumpur. Airlines have been urged to speed up refunds and give timely information to passengers.

Risks to residents

No tsunami warning has been issued, but the health ministry urged residents in affected areas to stay indoors and wear face masks to protect against respiratory, eye and skin irritation. Several schools cancelled activities on Saturday after students reported eye irritation from the ash, and, according to CNN Brasil, schools in Jakarta and Lampung switched to remote learning. One local resident told the BBC he began feeling eye irritation on Friday evening, describing it as feeling like "small grains of sand" in his eyes, and said he had to sweep his yard every five minutes because of the thick dust.

Volcanologist Surono told CNN Brasil that flying is currently dangerous because sulfur- and silica-laden ash can damage aircraft engines, while visibility is poor due to a lack of rain, adding that this eruption's behavior has been unusual.

President Prabowo Subianto chaired a virtual meeting on Monday about the situation, linking it to the August 15 earthquake that killed more than 130 people in eastern Indonesia and to ongoing forest fires, saying the disaster-mitigation budget needs to be significantly increased and that more helicopters and water pumps are needed.

Historical background

Anak Krakatau emerged about a century ago within the caldera left by the legendary 1883 eruption of Krakatoa, which killed more than 36,000 people and destroyed 165 villages in under 48 hours — the BBC notes it also produced what is considered the loudest sound ever recorded. In December 2018, part of the volcano collapsed into the sea, triggering a tsunami that killed more than 400 people along the coasts of Sumatra and Java. The volcano lies on the Pacific Ring of Fire, where about 90% of the world's earthquakes occur and which is home to 75% of the planet's active volcanoes.