Mount Agung on the island of Bali has been in continuous eruption since Saturday November 25, 2017. But it’s hard to know what will happen next.
A large plume of volcanic ash is visibly spewing from the volcano.
“The eruption is ongoing with the plume reaching between 2.5 and 3 km,” said Christina Magill, Senior Lecturer in Environmental Sciences at Macquarie University.
“The ash cloud has now travelled approximately 400 km southwest of Agung, and is moving towards Tropical Cyclone Cempaka that is currently sitting just south of Java.”
It also appears that molten rock is coming to the surface of the volcano.
“Last night the NASA Modis satellite detected a thermal anomaly in the crater of Mount Agung, suggesting a significant volume of magma has been brought to the surface.”
Magma is a mixture of molten and semi-molten rock found under the surface of the Earth - when it reaches the surface it is known as lava.
There are continuous tremors in the area, and the alert level has been raised to the highest level of 4 around Mt Agung.
A 10km evacuation zone has been established around the crater, and officials say 22 villages and about 90,000 to 100,000 people are directly affected.
“Although a larger eruption is possible, it is difficult to estimate the likely intensity of future activity,” Magill said.
The closure of Bali’s I Gusti Ngurah Rai International Airport is now extended to 7am on the 29th of November, with evaluations continuing to be made by the airport authorities.
“Darwin Volcanic Ash Advisory Centre has a current aviation alert for Agung volcano covering the area southwest of the volcano including Bali and southeast Java” said Magill.
“There are reports of ash on the runway at Denpasar airport.”
Denpasar is the main urban centre on Bali.
For the latest news, Associate Professor Heather Handley from Macquarie University recommends keeping an eye on twitter updates from the Indonesian Centre for Volconology (@ID_magma) and Sutopo Purwo Nugroho (@sutopo_BNPB), a representative of the Indonesian National Disaster Management Authority.
Since then, there have been two known periods of activity at the volcano site without an ensuing eruption.
On the neighbouring island of Java, the explosive 2010 eruption of Mount Merapi saw more than 400,000 people evacuated and 367 killed. This was preceded by increased earthquake activity over a period of about two months. It was the volcano’s largest eruption since 1872.
In 2010, the Indonesian Centre of Volcanology and Geological Hazard Mitigation issued timely forecasts of the size of the eruption phases at Merapi, saving an estimated 10,000–20,000 lives.
“The Indonesian authorities are doing an incredible job of co-ordinating people on the ground, and keeping everyone up to date on the latest activity and hazards of Agung,” said Handley.
The Conversation will continue to provide scientific analysis over coming days.
Authors: Sarah Keenihan, Section Editor: Science + Technology, The Conversation