Indonesian Volcano Mount Agung is Stirring. How Bad Could an Eruption Be?

Fagjun | Published 2017-11-29 02:13

Tens of thousands of people on the Indonesian island of Bali have been told to evacuate because the volcano Mount Agung has shown signs of an imminent eruption.

Mount Agung is waking up. [Photo by Antara Foto]



Mount Agung is one of 78 active volcanos on the Indonesian archipelago’s 13,000 islands. Indonesia is second only to Japan in the number of known volcanic eruptions, but Indonesia has the most number of deaths tied to volcanic activity. According to one study, Indonesia has seen 160,000 deaths related to volcanic eruptions from 1600 to 1982. The country sits on a region called the Ring of Fire, which is the most seismically active region in the world. Of course, with seismic activity often comes volcanic activity as well.


1963 marked the last time that Mount Agung erupted. Over 1,100 people died as a result of that eruption. Now that Mount Agung is showing signs of another eruption, people are wondering if this will be a repeat of the deadly 1963 disaster.

A Repeat of History?

The 1963 eruption and the 2017 volcanic activity with the same structure in the foreground of the volcano [Photos by Indonesia Historical (left) and Reuters (right)]



Indonesian authorities, thankfully, are not taking any chances. The volcano alert status is at the highest possible level, and 100,000 people living in the 10-kilometer radius around the volcano have been told to evacuate. About 40,000 people have already fled. Bali and Lombok have also shut down their airports.


Experts are giving serious warnings on the devastation that an eruption might bring upon the surrounding areas. According to planetary geosciences professor David Rothery, due to an increase in population density, there would be more deaths than the 1963 eruptions if evacuations didn’t take place.


Villagers evacuating away from the volcano [Photo by Firdia Lisnawati, AP]



Mark Tingay, a volcanologist at the University of Australia, also says that the magma in the region is characteristically very viscous. This means that the magma can trap more gas bubbles, leading to a bigger explosion. Tingay has also noticed that the volcano has been in a magmatic phase since around the 25th of November. Hot magma is therefore likely building up from underneath the volcano.


Mount Agung has been showing signs of a possible impending eruption since September of this year. There were changes in the patterns and intensity of the earthquakes occurring under the volcano, so evacuations began then. Fortunately, the volcano didn’t erupt right away. However, this isn’t exactly a good sign. The 1963 eruption was preceded by almost a year of volcanic activity, which included small explosions, ash emissions, and lava flows.

An Eye on the Volcano

Lahar flows in the villages near the volcano



The biggest potential threat to human life now is the pyroclastic flows, which in the 1963 eruption came after the year-long volcanic activity. Pyroclastic flows include hot ash and lava blocks, as well as pumice, all of which shoot down the slopes of the volcano at high speeds. MAGMA Indonesia, the country’s volcano monitoring center, says that aside from pyroclastic and lava flows, ashfalls and mudslides are also hazardous to anyone near the volcano. Rainfall can also make things worse, as rainfall and ashfall can combine to create lahar, which can potentially be more destructive than the eruption itself.


If the 1963 eruption is anything to go by, the volcanic activity on Bali likely won’t subside anytime soon. However, monitoring agencies will be keeping a close eye on this young, deadly volcano.

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