Simple flaw in warning system
Nyoman Kasna, a local Balinese official, is taking his role incredibly seriously. For him, this is quite literally a move that could determine life or death, as officials report the mighty Mount Agung is “inflated” and “swollen”.
“Sirens will sound and tell the community the mountain has erupted.”
Officials this week installed warning sirens in several townships beneath a rumbling volcano on the Indonesian holiday island of Bali, where an ancient crater is spewing steam and sulphurous fumes with more intensity, heightening fears of an eruption. So far, officials have evacuated more than 144,000 people.
The hope of the special warning system, which will be triggered manually when the volcano erupts, is to give residents enough time to flee.
As reported by news.com.au, the issue for experts attempting to map out a possible eruption timeline in Bali is the fact that no one really knows when the giant volcano will blow.
It could be in the next ten minutes. Or the next hour. It could be not at all. But the latest evidence collected by Indonesian officials shows the likelihood continues to increase.
“Based on the analysis of current monitoring data, at this moment, the probability of an eruption is higher than the probability of no eruption.”
Mount Agung, 75 kilometres from the resort hub of Kuta, has been shaking since August and threatening to erupt for the first time since 1963. Fear it will blow is already impacting the island’s lucrative tourism industry.
“There are volcanic eruptions going on all the time but this one is so unique because there’s such a high denisty of people and a lot of people who are tourists,” New Zealand volcanologist Dr Janine Krippner told news.com.au.
“The whole world is watching.”
But the siren used to protect them all has one potentially fatal flaw — its radius is only 2 kilometres, which, Dr Krippner admits “is not that large”.
She said early warning systems for volcanos were more complicated and less easy to identify.
“It’s not like an early warning system you have with a tsunami. With a tsunami, the ocean can feel that the wave is coming.”
What authorities have predicted justifies the need for a bigger and better system because, despite the unknown nature of the impact of this massive volcanic beast, the visuals are quite terrifying.
The graphic below shows the potenital route of pyroclastic flow — a combination of rocks, gas and ash expelled from a volcano — and lahars, which are rivers of water, mud and volcanic debris.
“This is a hazard map that is based on people looking at the geological record around the volcano and seeing where the deposits have gone in the past,” Dr Krippner explained.
The Indonesian Center for Volcanology and Geological Hazard Mitigation said Friday that remote satellite sensing had picked up new steam emissions and thermal areas within the crater.
White steam clouds — which contain sulphurous fumes — have been observed rising 50m to 200m above the summit, the centre said.
“This morning the steam billowed from the crater like the smoke that comes out of a factory chimney,” Gede Suandika, from the The Indonesian Center for Volcanology and Geological Hazard Mitigation, said.
“Since the sulphurous fumes are out, the possibility of an eruption is getting more real.”
According to MAGMA Indonesia, which measures volcanic data from Mount Agung, recorded “brittle failure inside the volcano caused by magma movement”, in its most recent update.
Volcanic earthquakes are estimated to be located within 20km of the volcano’s summit.
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“More earthquakes are being felt recently by people around Agung and Batur areas, and some of the biggest earthquakes are even felt in Denpasar and Kuta areas,” said Kasbani, the Indonesian Center for Volcanology and Geological Hazard Mitigation’s head volcanologist.
It’s little relief for survivors from the last eruption, who told the BBC they saw a “huge cloud above the mountain” at the time.
“That cloud fell to the earth in lumps. It sounded like lots of bombs going off,” one elderly man recalled.
The airport in Bali’s capital Denpasar, through which millions of foreign tourists pass every year, has not been affected, but several countries including Australia and Singapore have issued travel advisories warning visitors to exercise caution.
In case of an eruption, Indonesia plans to divert flights headed for Bali to 10 other airports, including on nearby Lombok and the capital Jakarta.
Mount Agung’s last eruption more than 50 years ago killed nearly 1,600 people.
Indonesia is the world’s most active volcanic region with 127 active volcanoes. The Southeast Asian archipelago lies on the Pacific “Ring of Fire” where tectonic plates collide, causing frequent seismic and volcanic activity.
– Australian travellers to Bali should visit the Australian Government’s Smart Traveller website.
— Additional reporting by AFP