Bagana, an andesite lava cone on Bougainville Island, Papua New Guinea, is
thought to be a very young central volcano. We have tested this idea by estimating
the volumes of lava extruded over different time intervals (1-, 2-, 3-, 9-, 15-, 70-
years) using digital elevation models (DEMs), mainly created from satellite data. Our
results show that the long-term extrusion rate at Bagana, measured over years to
decades, has remained at about 1.0 m3s-1. We present models of the total edifice
volume, and show that, if our measured extrusion rates are representative, the
volcano could have been built in only ~300 years. It could also possibly have been
built at a slower rate during a longer, earlier period of growth. Six kilometres NNW of
Bagana, an andesite-dacite volcano, Billy Mitchell, had a large, caldera-forming
plinian eruption 437 years ago. We consider the possibility that, as a result of this
eruption, the magma supply was diverted from Billy Mitchell to Bagana. It seems that
Bagana is a rare example of a very youthful, polygenetic, andesite volcano. The
characteristics of such a volcano, based on the example of Bagana, are: a
preponderance of lava products over pyroclastic products, a high rate of lava
extrusion maintained for decades, a very high rate of SO2 emission, evidence of
magma batch fractionation and location in a trans-tensional setting at the end of an
arc segment above a very steeply dipping and rapidly converging subduction zon
Is data on this page outdated, violates copyrights or anything else? Report the problem now and we will take corresponding actions after reviewing your request.