Geologists on the southern rim of Santa Ana's summit crater stand above the hydrothermally altered walls of the more than 100-m-deep inner crater. A near-vertical fault is visible in the far northern wall of the larger crater beyond the crater floor in the center of the photo, above the inner crater. Lava flows exposed in the crater wall are overlain by a roughly 10-m-thick light-brown sequence of phreatomagmatic tephra layers.

Photo by Paul Kimberly, 2002 (Smithsonian Institution).

This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.

Keywords: crater | vent | sulfur | stratigraphy | outcrop | geology | mineral deposit | tephra | hydrothermal alteration | field work

Santa Ana