In case you don’t frequent the NASA Earth Observatory, I thought I’d call your attention to some images they recently posted that are, again, excellent shots of volcanism captured from space.
The current plume from Tavurvur Crater at Rabaul was shot by the MODIS imager on Terra in early August. The plume is mostly made of volcanic gases and steam, but minor amounts of ash are also found – and remember, even small concentrations of ash in the air can be hazardous to aircraft.
Shiveluch has been having a busy summer, with moderate-to-large plinian eruptions produced by the emplacement (and destruction) of a new dome at the summit. This MODIS image (taken from the Aqua satellite) shows both the plume heading out over the Bering Sea and also the the extent of the ash fall on the Peninsula – along with the deposits from pyroclastic flows or lahars (most likely) on the west (left) side of the volcano.