Global Volcanism Program | Image GVP-10378
Gases rise from the hydrothermally altered western wall of Santa Ana's inner summit crater above the acidic lake. A steep path down the NE crater wall (far right) provides access to the lake for geochemical sampling. Sequences of phreatomagmatic tephra units more than 100 m thick are exposed in the walls of the outer summit craters.
Photo by Paul Kimberly, 2002 (Smithsonian Institution).
This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.