Nyiragongo volcano
The upper image, taken by the Advanced Land Imager on NASA’s Earth-Observing 1 satellite shows Nyiragongo volcano near the border between the African nations of Rwanda and the Congo. It sits in the African rift zone and is one of the most active volcanoes in the area, regularly forming lava lakes. The lower images show the Alaskan volcano Veniamanof, described in this recent post.
Compared to the image of Veniamanof, the Nyiragongo cloud looks different; the cloud coming out of this volcano is mostly gases such as steam that were dissolved in the magma, whereas the plumes from Veniamanof contained both steam and ash because that volcano is more explosive. The gases from Nyiragongo are departing the volcano but they’re coming out easily because the magma is lower viscosity (effectively less sticky).
Simply from satellite imagery you can gain information on the type of eruption going on, how dangerous it is, and even what type of rock is involved.
-JBB
Image credit: http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=81807
Volcano information and update: http://www.volcano.si.edu/volcano.cfm?vn=223030