Moi, Paul Derand

Moi, Paul Derand

Sulawesi's most dangerous volcanoes

These are all Sulawesi volcanoes that have erupted in the last 500 years, that have a Volcanic Activity Index (VAI) of at least 1 and that have the potential to threaten more than 10,000 people during one eruption. They are classified by their dangerosity (depending of the VAI and the number of people eventually threatened): class 0 is very little to little, class 1 is a little to moderate, class 2 is dangerous to very dangerous, class 3 is very dangerous, class 4 is extremely dangerous. Values superior to 4 can be used if necessary.

 

Awu (dangerosity 1,2):

Awu is a sub-plinian volcano on Sangihe island.

It has a VAI of 1,26, which is moderate.

Deep valleys that form passageways for lahars dissect all the flanks of the 1320-m-high volcano. Awu is one of Indonesia's deadliest volcanoes; powerful explosive eruptions in 1711, 1812, 1856, 1892, and 1966 produced devastating pyroclastic flows and lahars that caused more than 8000 cumulative fatalities. Pyroclastic flows and lahars passing by the valleys could threaten West Tahuna, North Tabukan and eventally Tahuna, that have a total population of up to 25K people.

Moreover, these pyroclatic flows and lahars, without forgetting moderate ashfall, would be able to destroy or at least to bury the Naha airport under up to 75 cm of ash. It is the only airport used by all inhabitants of Sitaro and Sangihe island groups (total population of 190K people). This poses a problem as the only other way to access these islands is by boat, and it takes several hours, not a good solution to evacuate injured or sick people (that might be numerous in case of an eruption).

 

Karangetang (dangerosity 2,6):

Karangetang is a vulcanian (VEImax=3) volcano located on Siau island. It is very frequently active (it has a VAI of 2). Twentieth-century eruptions have included frequent explosive activity sometimes accompanied by pyroclastic flows and lahars. Lava dome growth has occurred in the summit craters, collapse of lava flow fronts has also produced pyroclastic flows. Up to 20K people of East and Northwest Siau island might be threatened by eruptions from Karangetang.

 

Lokon-Empung (dangerosity 2,1):

Lokon-Emung it a vulcanian (VEImax=3) volcano in North Sulawesi. It has a VAI of 1,96 (moderate to high), as it is frequently active.

Historical eruptions have primarily produced small-to-moderate ash plumes that have occasionally damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred. It is located in the immediate vincinity (4 km to the NW) of the 94K inhabitants city of Tomohon. Any explosive eruption would damage croplands and houses up to 20 km away (563K people including the cities of Manado, Tomohon and Tondano) with ashfall. Moreover an eruption with a lava dome might produce pyroclastic flows reaching the northern part of Tomohon.



26/03/2015
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