Bali’s Mount Agung has been on the highest alert level for just over a month now and despite declining seismic activity, the volcano remains a level IV, as of Monday morning.
Volcanologists are keeping Agung on level IV, based on a comprehensive analysis of various parameters, including seismic activity, deformation, geochemical activity, and satellite imagery, according to Kasbani, head of the Volcanology and Geology Disaster Mitigation Agency (PVMBG).
“Although the activity has declined, it (seismicity) remained high, Antara Bali quoted Kasbani as saying.
In the past month since the alert level was raised to level IV for Agung on Sept. 22, seismic activity has greatly fluctuated, with the highest frequency being 1,047, but on Friday, Oct. 20, just 379 volcanic earthquakes were recorded.
But eruptions elsewhere on the Indonesian archipelago are another factor that have volcanologists hesitant to downgrade Agung. Mount Merapi in Central Java erupted in 2006 after seismic activity had been low, while Mount Sinabung in Sumatra erupted in 2013 after its status was reduced to level III, according to Kasbani.
And visual observation has shown significant structural change at Agung, including cracks at the crater. White steam clouds going up into the sky, 100 to 500 meters high, have bee observed, along with the formation of new hot areas on the northeastern and central part of Agung’s crater surface.
Satellite imagery additionally showed water coming out from the crater, suggesting a hydrologic disturbance deep inside Agung, due to the movement of magma.
Kasbani also said that GPS readings showed Agung experienced volcanic inflation at its peak, with an increase of as much as six centimeters, from September to October 2017, so far.
All this has led analysts to believe an eruption from Agung is more likely no eruption, it’s just a matter of when.
As long as Agung remains on the highest alert level for an eruption, tens of thousands of evacuees who fled their homes from inside the danger zone of 12 kilometers from Agung’s crater must live as refugees. The government has declared a state of emergency to handle evacuees from Agung and will keep extending the status if Agung continues to be a level IV.
