Close-up view down into the roiling pool that occupies the summit crater of Korovin volcano. Rivlets of ash can be seen that have run back down into the bare rock margin around the pool.
McGimsey and others (2008) and Neal and others (2009) detail satellite imagery and field observations of ash on the upper east flank of Korovin volcano in late June - early July, 2004, likely from a small phreatic eruption of Korovin prior to late June.