Speculating on the 2011 Nabro eruption in Eritrea

The eruption of Nabro in Eritrea has been a bit of an enigma, mostly because the volcano is (a) so remote and (b) it's previous activity is mostly unknown. In fact, when the eruption was first identified by the Toulouse VAAC, it was mistakenly attributed to the nearby volcano Dubbi, mostly because Dubbi has had an historical eruption in 1861 while Nabro, well, it is not known when the caldera system had it's most recent eruption (likely in the last 11,0000 years is the best guess). This makes interpreting the current activity, and more importantly how the eruption will proceed, very difficult. We have been fortunate that the volcano has, for the most part, been visible on satellite images of the area just south of the Red Sea, so the light grey/tan plume was captured speeding across northern Africa. Beyond this, though, we didn't have a lot of information from the ground to understand what sort of eruption was occurring at Nabro.