A new intense explosion has occurred on top of the Sinabung volcano in Indonesia.
During the middle of this morning, a new powerful explosion occurred on top of the Sinabung volcano, a 2,460 m high stratovolcano on the island of Sumatra, Indonesia.
The explosion produced an eruptive column that rose about 4.5 km in altitude, causing a modest fallout of ash and lapilli along the entire southeastern side of the volcanic edifice. Also along the eastern and south-eastern slopes, the volcano generated a dense and extremely dangerous pyroclastic flow that covered about one kilometre from the top of the crater. This flow did not affect inhabited areas and consequently did not cause any particular inconvenience.
Today's explosive event did not cause any injuries or victims, especially since this type of explosion has been occurring at the top of the Sinabung volcano for almost a year. The first notable explosion occurred almost exactly one year ago, on 10 August 2020. In that case, the local authorities evacuated all villages within a 3-5 km radius of the top of the volcano. Also in August 2020, the volcano's eruptive activity changed from a purely explosive activity to a predominantly extrusive activity, i.e. a type of eruption in which the lava emitted by the volcano accumulates in the same area from which it emerges, thus generating a lava dome.
As we learned very well during the March-April eruption of the La Soufrière volcano in the Caribbean, lava domes are nothing more than an accumulation of very viscous lava that solidifies in place and grows progressively, which increases the risk of explosive activity that gives rise to frequent and very dangerous pyroclastic flows. In fact, these lava domes are not very stable and often tend to collapse completely or to crumble slowly, something that was already happening at Sinabung during the first days of February this year.
The volcanic alert has since been upgraded to level 3, and in March the volcano produced an intense explosion that generated several pyroclastic flows that travelled over 5 km along the slopes of the volcanic edifice. During that particular explosion, a good portion of the lava dome that had formed at the top of the crater was completely collapsed.
Since then, apart from sporadic, rather weak explosions, eruptive activity had returned to the extrusive phase, with the lava dome slowly increasing in size again. It is too early to know whether today's explosion has again shrunk the lava dome at the top of the crater, but explosions like today's are not unusual or unexpected for Sinabung.
Photo: Beidar Sinabung, Firdaus Surbakti.