Image: Mount Agung in early December, 2017. Credit. ST.
THE CENTRE of Volcanology and Geology Disaster Mitigation (PVMBG) has set the safety exclusion zone narrower today for activities around Mount Agung from 8-10 kilometres to six kilometers.
“Although the status of Mount Agung is still set at the top warning level of “beware”, we have narrowed the safe radius of activities from 8-10 km to six kilometer,” said the Minister of Energy and Mineral Resources, Igansius Jonan at a press conference today in Jakarta. “Based on visual and instrumental data analysis at the moment Mount Agung was still in an eruption phase with relatively high and fluctuating volcanic activity. Lava is still in the crater, blowing and blasting ash and rock debris around the crater,” he said to antaranews.com.
He also said that the lava volume inside the crater was around 20 million meter cubic, or a third of the total volume of the crater, which is 60 million meter cubic. The growth of the dome was still low so the lava won’t fill the crater in the near future.
Jonan also said that the Mount Agung status with high and low frequency tremors were still being recorded that indicate the magma pressure and flow from inside to the surface. “But, the power of the tremor has not significantly increased,” he said.
Besides, deformation data recently also showed a stagnant trend that indicated no significant increase to the pressure inside. “Meanwhile, recent geochemical data still showed magmatic gas SO2 with a flux of around 100-300 tons daily,” he said.
The potential danger estimated right now is the incandescent rock, gravel and thick ash that could strike the area around 6 kilometres from the crater. Meanwhile, the mudflows will follow the river valleys that come from Mount Agung depending on the amount of water and eruption material volume.
With the recent scale of eruptions, which is intermittent, the potential for a dangerous hot cloud is still low, because the slow lava growth that is filling the crater, which would need a huge amount of power to destroy the lava dome and to transform to a hot cloud. There was no significant increase to the pressure right now.
That’s why Jonan recommended the status was still “Beware”, but the safe radius is now smaller. “We still set the same status because at the moment Mount Agung was still in an eruption phase and could impact those surrounding areas,” he said.
The other recommendation is to keep aware of any fast changes, and to anticipate those changes.