Santa Ana, El Salvador's highest volcano, is a massive, 2381-m-high stratovolcano whose summit is truncated by a series of four nested craters, seen here from the SW. A series of parasitic vents and cones have formed along a 20-km-long fissure system that extends from the low NNE flank to the San Marcelino and Cerro Chino cinder cones on the SE flank. Historical eruptions, largely consisting of small-to-moderate explosions from both summit and flank vents, have been recorded since the 16th century.

Photo by Mike Carr, 1982 (Rutgers University).

Photos in the Types and Processes Gallery

Thermal activity at the surface of a volcano is evidence of volcanic heat below. The fumarolic activity seen here produces vigorous steam plumes along the sulfur-encrusted wall of the summit crater at El Salvador's Santa Ana volcano. Thermal activity is common during non-eruptive periods at many volcanoes and may persist for many thousands of years. In addition to the fumarolic activity in this photo, the interaction of high-temperature volcanic fluids and gases with groundwater in hydrothermal fields can produce geysers, hot-spring pools, and mudpots.

Photo by Kristal Dorion, 1994 (U.S. Geological Survey).

Additional Photos

Cerro Verde, a 2030-m-high satellitic cone of Santa Ana volcano, is seen here from the NW above Hacienda San Blas. Cerro Verde is near the SE end of a 20-km-long eruptive fissure that cuts across Santa Ana from its lower NNE flank. Three N-S-trending craters are located at the summit of Cerro Verde, and a fourth is located on the SE flank of the cone.

Photo by Kristal Dorion, 1994 (U.S. Geological Survey).

The broad summit of Santa Ana volcano is seen here from Cerro Verde, a satellitic cone on its SSE flank. A series of four nested craters, the largest of which is 1.5 km wide, truncates the summit. Houses of Hacienda San Blas are visible at the bottom of the photo. Much of the slopes of Santa Ana are covered with coffee plantations that are an important part of the local economy.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).

Santa Ana's active crater, partially filled by an acidic crater lake, lies at the SE end of a series of four nested craters. This photo is taken from the northern rim of the next-to-youngest crater and shows a broad bench whose surface is dotted by several small phreatomagmatic vents formed during historical eruptions.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).

Scoria from the 1904 eruption of Santa Ana volcano form the darker deposits blanketing the rim of the summit crater. The first of two 20th-century eruptions from Santa Ana began on January 12 and lasted for about two weeks, during which phreatomagmatic explosions ejected these scoriae.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).