Anak Krakatau Eruption Shuts Eight Indonesian Airports

A volcanic eruption from Anak Krakatau has caused major disruption to air travel in Indonesia, forcing authorities to suspend operations at eight airports, including Jakarta's main international airport, Soekarno-Hatta.

The eruption also affected schools, fishing activities and maritime traffic around the volcano.

Anak Krakatau erupted on Saturday, producing lava and powerful booming sounds that were reportedly heard as far as 700km away, according to Indonesia's geological agency.

The volcano erupted twice more on Sunday.

The resulting ash cloud spread across surrounding airspace, creating a serious hazard for aircraft.

At Soekarno-Hatta airport, located near Jakarta, volcanic ash was detected in the airspace, prompting authorities to suspend flights.

The closure was repeatedly extended and the airport was expected to remain closed to flights until 9.30pm local time on Sunday.

Hundreds of flights, including international services, were affected.

More than 22,000 passengers and 209 flights were affected overall, according to Indonesia's transport ministry.

The disruption was particularly significant on routes between Indonesia and Singapore.

Singapore Airlines cancelled its flights to and from Jakarta for the rest of Sunday, while Qantas reported cancellations and other disruptions affecting its Jakarta services.

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

At least 16 domestic flights to Bali were also cancelled.

The main reason for the flight restrictions is the danger volcanic ash poses to aircraft.

Ash particles can enter jet engines, melt onto extremely hot internal components and damage turbine blades.

They can also clog fuel and air systems and impair pilots' windscreens.

Even though volcanic ash may look like an ordinary cloud from a distance, flying through a concentrated ash plume can therefore pose a serious safety risk.

Airlines said they were monitoring conditions and would resume services when it was safe to do so.

The ash plume reached significant altitudes.

Indonesia's meteorological agency, BMKG, reported ash at heights of up to 6,000 metres on the Java side of the volcano and as high as 15,000 metres on the Sumatra side and over parts of Banten province in Java.

These altitudes put the ash directly into airspace used by commercial aircraft, explaining the scale of the disruption.

The eruption has also affected people living near the volcano.

Several schools cancelled activities on Saturday after students and residents experienced eye irritation caused by the ash.

Local fishermen also cancelled trips because of the hazardous conditions.

Indonesia's disaster mitigation agency, BNPB, said it planned to carry out weather modification operations, potentially including cloud seeding, in an attempt to encourage rainfall.

Officials said sufficiently heavy rain could wash volcanic ash out of the air and help reduce its impact on daily life.

Anak Krakatau, whose name means "Child of Krakatau", lies in the Sunda Strait between the Indonesian islands of Java and Sumatra.

It emerged from the caldera left by the catastrophic 1883 eruption of Krakatau, one of the deadliest volcanic eruptions in recorded history.

Around 35,000 people died in that disaster, which generated enormous explosions and tsunamis.

The current eruption is not reported to have caused comparable loss of life, but authorities have imposed restrictions around the volcano.

Ships travelling through the Sunda Strait have been prohibited from approaching within two miles of Anak Krakatau and have been warned to remain vigilant.

The incident highlights how volcanic eruptions can have consequences far beyond the immediate area around a volcano.

In this case, an eruption on a relatively remote island has disrupted one of Indonesia's most important international aviation hubs, stranded tens of thousands of passengers and affected international connections across south-east Asia and beyond.

Authorities and airlines are continuing to monitor the ash cloud and volcanic activity before deciding when normal flight operations can safely resume.