Emergency sirens to provide early warning to people in the event of a volcanic eruption have been installed around Mount Agung, while plans to divert flights are being drawn up as the authorities in Bali prepare for what is feared to be an imminent eruption of the volcano.
The number of evacuees rose from just under 76,000 on Tuesday to more than 96,000 yesterday, according to Indonesia's National Disaster Management Agency (BNPB) spokesman Sutopo Purwo Nugroho.
Volcanic activity near Mount Agung remains high, with hundreds of tremors - including both shallow and deep earthquakes - recorded overnight, he said.
"The number of earthquakes was more than last Tuesday… and magma movement approaching the surface continues, with the chances of an eruption quite high," said Dr Sutopo. "But it cannot be certain when it will erupt."
The BNPB has installed five iCast Rapid Deployment Public Notification System mobile sirens around Mount Agung. People within a radius of 2km should be able to hear the sirens, which will be manually activated by a duty officer at the BNPB command post in Karangasem regency, where the volcano is located.
The number of evacuees is expected to grow, despite already reaching 96,086 yesterday.
These people are spread across 430 shelters in nine different regencies, but the basic needs of those seeking shelter are sufficient so far, said Dr Sutopo.
"The Balinese people have been a big help for the evacuees," he said. "Gotong royong, solidarity and cohesiveness of the community has led to how well the evacuees are being handled." Gotong royong means teamwork in Bahasa Indonesia.
In anticipation of an eruption, Indonesia also plans to divert flights headed for Bali to 10 other airports, said the Ministry of Transportation.
A ministry spokesman yesterday said the 10 airports are located in the capital Jakarta, and in Ambon, Balikpapan, Banyuwangi, Kupang, Makassar, Manado, Praya, Solo and Surabaya.
These will serve as alternative airports for aircraft en route to Ngurah Rai airport, which will be closed if it is affected by volcanic ash from Mount Agung, said Transportation Minister Budi Karya Sumadi.
"The flights will be diverted to the nearest location or to where they originated from," he said.
The minister was speaking to his staff on Tuesday after a meeting with his counterparts at the 4th Asia-Europe Meeting, which is being held in Bali's capital Denpasar until today.
Denpasar, where Ngurah Rai airport is located, is about 70km away from Mount Agung.
It remains safe, but could be affected if a thick ash cloud follows an eruption, said officials.
An estimated 5,000 travellers may be affected if the international airport is shut, but the ministry has prepared 100 buses to take passengers to Banyuwangi, Praya or Surabaya, where they can arrange for alternative flights home.
People familiar with the route, including seasoned travellers to Bali, told The Straits Times yesterday that if the airport in Denpasar is shut down, travellers can still easily make their way over land and sea to Java, where there are many airports to fly out from.
"You can still go by car to Gilimanuk port where you can cross the Bali Strait by ferry to Banyuwangi in East Java," said Mr Herman Winarto, a diving instructor in Bali.
"From there, you can travel by car, bus or train to other destinations in Java, such as Surabaya, Yogyakarta, Bandung, and then catch a flight out of Indonesia from Jakarta."