BY ARMAND VERVAECK
Just northeast of Bagana, one of 17 volcanoes on Bougainville, is the volcano crater lake, Billy Mitchell.
Bagana is a massive symmetrical lava cone about 1,750-metres high, largely constructed by an accumulation of lava flows. The entire cone could have been constructed in about 300 years at its present rate of lava production.
Bagana is poorly monitored. Located on the mountainous spine of Bougainville, it is far from any large towns and hard to reach due to the rough terrain.
Bagana emits volcanic gases (including water vapour and sulphur dioxide) almost continuously, and frequently extrudes thick lava flows. Satellites provide the most reliable way to watch this activity.
This natural-colour image, collected by the Earth Observing-1 satellite on 16 May, reveals a fresh lava flow on Bagana’s eastern flank.
Imagery from Landsat 7 shows that the flow was established some time between March 2011 and February 2012. The fresh lava is dark brown, while lighter brown areas were likely stripped of vegetation by volcanic debris or acidic gases.
Older lava flows are covered in light green vegetation, and the surrounding forests are dark green. The volcanic plume and clouds are both white.