Anak Krakatau eruption disrupts flights at Indonesia's main airport

Eruption and ash cloud

Anak Krakatau ("Child of Krakatoa"), a volcanic island in the Sunda Strait between Java and Sumatra, has shown heightened activity in recent days. According to the BBC and the Guardian, the eruption began late on Friday night, producing continuous seismic activity, lava fountains and booming sounds that, per Indonesia's geology agency, were heard as far as 700km away. The Associated Press (via CityNews Vancouver), however, reports that the actual eruption occurred early Sunday at 3:53am local time and lasted 30 seconds, with the volcano showing "signs of activity" on Saturday. Two further eruptions were recorded on Sunday.

Volcanologists and Australia's Darwin Volcanic Ash Advisory Centre identified two separate ash plumes: one rising to about 6,000m (20,000ft) and drifting northeast over Jakarta, Banten and West Java, and a second reaching roughly 15,000m (50,000ft) and moving west, covering parts of Lampung and Bengkulu provinces as well as areas of the Indian Ocean off Sumatra.

Impact on air travel

Once ash was detected in the airspace around Jakarta's Soekarno-Hatta International Airport — Indonesia's busiest — authorities suspended flight operations. The transport ministry reported 209 suspended flights affecting more than 22,000 passengers, with the shutdown repeatedly extended until 1:30pm local time. Airport operator Angkasa Pura, however, gave a higher figure of 301 affected flights, including 58 international ones. The AP report says the airport initially suspended operations only between 5:30am and 9:30am. In total, five airports halted operations. At least 16 domestic flights to Bali were cancelled, Singapore Airlines cancelled all its Jakarta flights for the rest of Sunday, and Qantas reported disruptions to a number of its services.

Effects on residents and precautions

No tsunami warning was issued, but Indonesia's health minister urged residents in affected areas to stay indoors and wear face masks to guard against respiratory, eye and skin problems. Several schools cancelled activities on Saturday after students and residents reported eye irritation, and fishermen called off trips at sea, according to local outlet Kompas. As reported by the BBC, one resident, Aldi Candra Prayogi, said he had felt as if "small grains of sand" had gotten into his eyes since Friday evening and needed eye drops, adding that he had to sweep his yard every five minutes because of the thick ash. Disaster agency BNPB, per the Guardian, plans to attempt weather modification, including cloud seeding, to trigger rain and wash the ash from the air.

The AP notes there have been no casualties and no evacuation order, with the nearest settlement more than 16km away, though authorities warned people to stay at least 3km from the active crater, and ships in the strait were barred from approaching within the same distance.

Historical background

Anak Krakatau emerged from the sea in the early 20th century inside the caldera left by the 1883 eruption of Krakatoa, one of history's deadliest, which killed an estimated 35,000 people, according to the Guardian. In December 2018, a partial collapse of the volcano triggered a tsunami that, per the BBC, killed more than 400 people, while the AP puts the toll at at least 430; rock fragments that slid into the sea at the time were up to 70-90m high. Indonesia sits on the Pacific Ring of Fire, an area of intense volcanic and seismic activity.