Indonesia's main airport suspends operations after volcanic eruption

Indonesia halted operations at its main international airport outside Jakarta on Sunday after ash spewed from the Anak Krakatoa volcano more than 150 kilometres away, impacting thousands of passengers.

Mount Anak Krakatoa erupted on Saturday, producing a fountain of lava and booming sounds that could be heard up to a few hundred kilometres away, the geology agency said in a statement.

Two new eruptions were recorded on Sunday, the volcanology agency warned.

Ash from the volcano was detected in the airspace surrounding Soekarno-Hatta International Airport, prompting authorities to initially suspend operations from 1:30 am Sunday (Saturday 1830 GMT) to 5:30 am.

The suspension was extended three times, with the latest ending at 5:30 pm Sunday "due to increased eruptive activity," the airport said in a social media post.

Operations have been suspended at six airports including the Hussein Sastranegara airport in Bandung and Radin Inten II airport near Bandar Lampung on Sumatra, the country's Transportation Minister Dudy Purwagandhi said.

Several airports in cities, including Semarang and Surabaya, have been prepared as "alternatives for landing" Dudy added.

The disruption left some passengers scrambling to find alternative flights.

Henny Yensan, 44, who had hoped to go back to her hometown with her mother, said "everybody was disappointed".

"No one flew into a rage, because after all, this is due to natural disaster," the businesswoman, who had to reschedule her flight to Tuesday, told AFP.

Samuel Guiberteau, a Danone executive on a business trip to Lombok since Friday, said "nothing is certain for the moment", as he searched for alternative flights back to the capital.

"I had found another flight on Citilink, but it was also cancelled," the 47-year-old told AFP by phone, adding that he had no alternative but to stay in Lombok for the time being.

More than 22,000 passengers have been impacted by the suspension, the transportation ministry said, adding that 209 flights were affected, in particular those to and from Singapore.

Other affected international routes included Doha, Sydney, and Kuala Lumpur.

At least 16 domestic flights to and from Bali were also cancelled, local airport authorities said.

Anak Krakatoa, which means Child of Krakatoa, sits in a strait that separates the islands of Java and Sumatra.

Ships passing through the strait were asked to increase vigilance for possible disruption to navigation safety due to volcanic activities.

The vessels are prohibited to approach the exclusion zone of three kilometres radius from the volcano, local port authorities said in a statement. 

The volcano has been sporadically active since it emerged from the sea at the beginning of last century in the caldera that formed after the 1883 eruption of Mount Krakatoa.

That disaster was one of the deadliest and most destructive in history with an estimated 35,000 people killed.

Geology agency head Lana Saria said "seismic activity indicates the movement or release of volcanic fluids within the volcanic system".

"However, the timing, magnitude, and nature of the next eruption cannot be precisely predicted," Lana added.

Lana warned against approaching Anak Krakatoa saying materials ejected from the volcano could endanger those within the exclusion zone.

She said the most recent series of eruptions do not have the potential to trigger a tsunami at this time.

A 2018 tsunami, triggered by a collapse of parts of Anak Krakatoa, killed 429 people and left thousands displaced.

Indonesia, a Southeast Asian archipelago nation, sits on the Pacific Ring of Fire, where the meeting of continental plates causes high volcanic and seismic activity.