Photograph showing summit crater of Shishaldin Volcano on August 1, 2008. The crater diameter is about 100 m (330 ft) narrowing to an inner throat that is about 30 m (100 ft) across (Vergniolle and others, 2004). The depth of the open conduit is highly uncertain and likely variable through time; Dehn and others (2002) estimated a depth of 400 m (1,300 ft) based on satellite image analysis and seismic source studies. Photograph by C. Read, AVO/USGS
Credit: Image courtesy of AVO/USGS.