February 3, 2014

expert reaction to Mount Sinabung eruption

Mount Sinabung in North Sumatra, Indonesia, erupted multiple times killing at least 16 people.

Prof David Rothery, Professor of Planetary Geosciences at the Open University, said:

“The Indonesian volcanologists have monitored events well, and issued reliable maps of the danger zones around Sinabung volcano which has been erupting since September.  Saturday’s fatalities at Sinabung illustrate the difficulties faced by local authorities during an ongoing eruption. 

“The people who died were apparently local tourists who had gone within the 5 km exclusion zone.  They were killed by a low density but very hot pyroclastic flow, of the kind that killed thousands at Pompeii during the AD 79 eruption of Vesuvius.  Significant risk of similar events, some larger, some smaller, may persist for several weeks more; but it is difficult to keep the curious away and to enforce evacuation of any local people who are reluctant to leave or who are determined to return to their homes.  

 “As well as the probability of further pyroclastic flows, the next heavy rain may turn rivers draining the area into torrents of dense mud, which can destroy bridges and other infrastructure at greater distances from the volcano.  Volcanic mudflows are known worldwide by the Indonesian name of ‘lahars’.

“Sinabung is only about 400km from Banda Aceh, the town that suffered greatest devastation from the 26 December 2004 Indian Ocean tsunami.  The earthquake that caused the tsunami is a result of the same plate tectonic process that leads to volcanic activity along the spine of Sumatra and the rest of Indonesia, which is that the floor of the Indian Ocean is being drawn down (subducted) below the edge of the Eurasian plate.”