Advertisement

Indonesia prepping for ‘worst case scenario’ after multiple eruptions from Mt. Sinabung volcano

Indonesia's Mount Sinabung has authorities on the island nation preparing for the 'worst case scenario' after the volcano erupted 77 times over the weekend, including one particularly violent eruption of ash, gas and lava on Sunday morning that sent residents still in the area fleeing down the mountainside.

Mount Sinabung — a 2,500 metre-tall volcano located near the northern end of Indonesia's island of Sumatra — has erupted several times over the past several months, after waking up from a three-year slumber in mid-September. The volcano's activity has been increasing since then, forcing the government to issue stronger alerts, and expand the evacuation area several times. The latest eruptions over the past weekend, 77 of them between Saturday and Sunday, basted ash up to around 4,500 metres into the sky, and produced pyroclastic flows that reached up to five kilometres down the volcano's southeast slope.

[ Related: Magma's balloon-like buoyancy drives super-eruptions ]

So far, the eruptions of ash and lava from Mount Sinabung have forced an evacuation zone extending up to a five kilometre radius around the volcano's crater, however, the zone was extended up to seven kilometres down the southeast slope, due to the increased activity there. As of the latest round of evacuations, more than 20,000 people have been forced from their homes, and are currently being housed in temporary evacuation centres.

Ahmad Nabawi, a member of the team monitoring the volcano, told the Jakarta Post that the flows seen so far only amount to about one-quarter of the 2.5 million cubic meters of volcanic material that Mount Sinabung has produced in its crater.

"This means that the pyroclastic potential stored in the volcano's lava dome is still substantial; so if it should all come out, the threat would be devastating," he said on Saturday.

Although lava is typically what we think of when it comes to volcanic eruptions, the main threat from Mount Sinabung is due to pyroclastic flows.

Unlike lava, which tends to flow fairly slowly, pyroclastic flows are fast-moving mixtures of super-heated rock and gases that can sweep down an erupting volcano at speeds of several hundred kilometres per hour. With such a mixture of material traveling so quickly, these are a particularly lethal form of eruption from a volcano. They're next to impossible to outrun, and victims are typically killed by the impact of the flow, incineration by the extreme temperatures, or asphyxiation due to the poisonous gases and displacement of air.

[ More Geekquinox: 'Polar vortex' hitting Canada, U.S. with brutal, bone-chilling cold ]

With authorities contemplating the worst case scenario, according to the Jakarta Post, the National Disaster Mitigation Agency (BNPB) has spread the word to all government agencies and local disaster relief programs to prepare for the evacuation zone to be extended to up to 7.5 to 10 kilometres away from the volcano.

According to the Wall Street Journal, Sutopo Purwo Nugroho, a spokesman for the BNPB, said that extending the evacuation zone to that far away would increase the number of displaced to nearly 60,000 people.

(Photo courtesy: Ulet Ifansasti/Getty Images)

Geek out with the latest in science and weather.
Follow @ygeekquinox on Twitter!