Coatepeque Caldera

Photo of this volcano
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 13.87°N
  • 89.55°W

  • 746 m
    2447 ft

  • 343041
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Coatepeque Caldera.

The Global Volcanism Program has no Weekly Reports available for Coatepeque Caldera.

The Global Volcanism Program has no Bulletin Reports available for Coatepeque Caldera.

The Global Volcanism Program is not aware of any Holocene eruptions from Coatepeque Caldera. If this volcano has had large eruptions (VEI >= 4) prior to 10,000 years ago, information might be found on the Coatepeque Caldera page in the LaMEVE (Large Magnitude Explosive Volcanic Eruptions) database, a part of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Photo Gallery


Coatepeque caldera, its eastern side filled by a caldera lake, was formed by collapse of a group of stratovolcanoes immediately east of Santa Ana volcano. The eastern caldera rim rises about 250 m above the lake surface. Post-caldera eruptions included the formation of basaltic cinder cones and flows near the western margin of the caldera and the extrusion of a half dozen rhyodacitic lava domes (such as the one forming La Isla at the right) along a NE-SW line near the caldera-lake margins.

Copyrighted photo by Dianne Neilson, 1972 (courtesy of Richard Stoiber, Dartmouth College).
See title for photo information.
The thick light-colored unit the volcanologist is pointing to is the Arce fall deposit, overlying a paleosol and mafic ash- and scoria-fall deposits. The biotite-rich rhyolitic Arce pumice-fall deposit was erupted from Coatepeque caldera about 72,000 years ago and was associated with formation of the SW part of the caldera. This outcrop is about 15 km NW of the caldera rim. Deposits of the 84,000-year-old Los Chocoyos Ash from Atitlán caldera in Guatemala lie about 3 m below the base of the Arce deposit, but are not visible in this photo.

Photo courtesy of Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
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Light-colored rhyolitic airfall pumice deposits from Coatepeque caldera are exposed in a quarry 20 km east of the caldera. These pumice-fall deposits blanket much of SW El Salvador, and along with associated pyroclastic-flow deposits have a volume of about 56 cu km. The earlier biotite-bearing Arce deposits originated during the largest eruption from Coatepeque about 72,000 years ago and are a half-meter thick at the Guatemalan border. The overlying Congo deposits originated during the second largest eruption of Coatepeque.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
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A volcanologist investigates an exposure of the Arce pyroclastic deposits on the eastern flank of Chilamatal caldera, about 10 km ENE of the rim of Coatepeque caldera. The Arce eruption about 72,000 years ago produced about 40 cu km of tephra and was associated with the first caldera-forming event at Coatepeque. The Arce deposits consist of two thick biotite-rich pumice-fall deposits, separated by thin ash-, pumice-, and lithic-fall deposits. Arce fall deposits are distributed over much of western El Salvador.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
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The forested Anteojos ("The Eyeglasses") lava domes form peninsulas on the eastern shore of Lake Coatepeque. Four other domes were constructed on the opposite side of the caldera along a line that passes through Izalco volcano to the SW. Most of the Anteojos domes lie beneath the lake surface and were once islands now connected by low spits to the caldera wall. The southern (near) dome is andesitic, whereas the northern dome has a rhyodacitic composition. Two scoria cones on the horizon erupted along caldera ring faults.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
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Rhyolitic pumice-fall and pyroclastic-flow deposits from the two caldera-forming eruptions (Arce and Congo) at Coatepeque are exposed in a quarry wall. The lower Arce biotite-bearing pumice-fall and overlying pyroclastic-flow deposit have a total volume about 40 cu km and were emplaced during the 72,000-year-old eruption that formed the NE part of the caldera. The upper deposits (above the brown paleosol in the center of the photo) are from the 16-cu-km Congo eruption prior to about 57,000 years ago and were erupted through a caldera lake.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
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Coatepeque caldera is seen here from the SSW at the summit of Cerro Verde, a flank cone of Santa Ana volcano. Lago de Coatepeque fills the NE part of the 7 x 10 km caldera. The younger SW side of the caldera partially truncates Santa Ana volcano and extends to the sudden break in slope seen in the lower part of the photo. The caldera floor is higher on this side as a result of the accumulation of volcaniclastic debris from Santa Ana volcano and the eruption of a series of post-caldera lava domes, one of which forms the island at the right-center.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
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Scenic Lago de Coatepeque fills the 7 x 10 km Coatepeque caldera in western El Salvador. The caldera was formed during two major eruptions in the late Pleistocene. Post-caldera eruptions produced a series of lava domes such as the one seen at the left, forming a small peninsula extending into the lake. A chain of cinder cones that erupted along caldera ring faults dot the southern caldera rim in the background.

Photo by Giuseppina Kysar, 1999 (Smithsonian Institution).
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Santa Ana volcano is seen here from the east on the rim of Coatepeque caldera. The eastern rim of Santa Ana's summit crater was breached and produced the gently sloping deposits extending towards the caldera lake at the lower right. The NW wall of the caldera in the background cuts into the flanks of Santa Ana volcano to a level about 800 m above the lake surface (lower right). This SW part of Coatepeque caldera was formed about 57,000 years ago during the eruption of about 16 cu km of rhyolitic pumice-fall and pyroclastic-flow deposits.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
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Lago de Coatepeque fills much of the eastern part of Coatepeque caldera. The NE part of the caldera (seen here from the southern caldera rim) was formed following the eruption of 40 cu km of rhyolitic pumice-fall and pyroclastic-flow deposits about 72,000 years ago. The northern caldera rim in the distance rises about 250 m above the lake, which has a maximum depth of about 120 m. Hot springs are located at several points along the shore of the lake near a group of post-caldera lava domes.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
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Cerro la Isla is the largest of a series of post-caldera lava domes extruded along a NE-SW-trending line within Coatepeque caldera. The summit of this 916-m-high dome, also known as Cerro Grande or Isla de Cabra (Goat Island), contains a shallow depression. The rhyodacitic dome, seen here from the southern caldera rim, rises about 90 m above the lake surface and about 180 m above the lake floor.

Photo by Paul Kimberly, 1999 (Smithsonian Institution).
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The SW part of Coatepeque caldera was formed about 57,000 years ago following the eruption of the roughly 16 cu km Congo biotite-bearing rhyolitic pumice-fall and pyroclastic-flow deposits. Plinian and phreatoplinian eruptions took place through a lake that formed in the NE part of the caldera, which had formed during the larger Arce eruption about 72,000 years ago. Post-caldera lava domes in the SW part of the caldera are seen in the middle ground.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
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An aerial view of the western side of Coatepeque caldera shows Cerro la Isla lava dome forming the island at the left center. On the ridge behind the caldera wall are (from left to right) the San Marcelino-La Olla and El Conejal-El Astillero pyroclastic-cone complexes, the tip of Izalco volcano, rounded Cerro Verde scoria cone, and (in the clouds) the summit of Santa Ana volcano. The Pacific Ocean is visible in the distance.

Photo by Bill Rose, 1967 (Michigan Technological University).
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Flat-topped Cerro Alto (right center), a 953-m-high cinder cone on the SE flank of Coatepeque caldera, is seen here from the southern rim of the caldera. Basaltic lava flows were erupted from the eastern side of the cinder cone. Cerro Alto predates formation of Coatepeque caldera and is blanketed by deposits from the caldera-forming eruptions. San Salvador volcano to the east forms the left horizon.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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Grass-covered San Marcelino cinder cone is seen from Cerro Chino on the SE flank of Santa Ana volcano. San Marcelino was formed during an eruption in 1722 and produced a lava flow that traveled 13 km to the east. The forested southern rim of Coatepeque caldera can be seen to the NE beyond and to the left of San Marcelino, and a small sliver of the surface of Lake Coatepeque is visible inside the caldera.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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The 7 x 10 km Coatepeque caldera forms a dramatic vista from the summit of Santa Ana volcano. The caldera was formed by collapse of a group of stratovolcanoes immediately east of Santa Ana volcano during a series of major explosive eruptions between about 70,000 and 57,000 years ago. Post-caldera eruptions included the formation of basaltic cinder cones and lava flows near the western margin of the caldera and the extrusion of rhyodacitic lava domes, including Cerro la Isla, the island at the W side of the caldera lake.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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A quarry exposes reddish oxidized scoria deposits with inter-bedded light-colored lava flows at Cerro la Leona cinder cone on the northern rim of Coatepeque caldera. The adjacent cones of Cerro la Leona and Cerro Cañitas on the NE caldera rim were bisected by the caldera ring faults. At least ten other basaltic scoria cones on the eastern and southern caldera rims form small hills that overlap the ring faults.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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The deep blue waters of Lago de Coatepeque fill the eastern side of Coatepeque caldera. Post-caldera lava domes, including the rounded island of Cerro Grande (Isla de Cabra) on the left at the far side of the lake and flat-topped Cerro Pacho (the low lighter colored area to its right below the caldera rim), were erupted along a E-W-trending line. The rounded hill on the right horizon is Cerro Verde.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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The western side of Coatepeque caldera at the top of the photo is seen from Cerro Chino cinder cone on the SE flank of Santa Ana volcano, which lies out of view to the left. The sloping rim of the caldera partially truncates the eastern side of Santa Ana. The western side of Coatepeque caldera is considered to have formed during the second stage of caldera formation associated with the eruption of the Congo Formation tephras and pyroclastic flows through a lake partially filling the earlier caldera.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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The road to the summit of Cerro Verde volcano provides a dramatic view of the eastern side of Coatepeque caldera. The hill at the right center is Cerro la Isla, a post-collapse lava dome. The caldera formed during two major explosive eruptions, the first of which occurred about 72,000 years ago and created the eastern part of the caldera in association with the Arce pumice-fall and pyroclastic-flow deposits. A lake partially filled the caldera floor prior to the Congo eruption associated with formation of the western part of the caldera.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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Santa Ana volcano rises above scenic Lago de Coatepeque. The 6-km-wide lake lies at the eastern end of the compound Coatepeque caldera. The northern and southern rims of the western side of the caldera are visible beyond the lake. The rounded peak to the left of Santa Ana is Cerro Verde, one of many cones constructed along a NW-SE-trending fissure cutting across the Santa Ana complex.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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The twin Anteojos lava domes form small peninsulas on the eastern shore of Lake Coatepeque. Four other domes were constructed on the opposite side of the caldera along a line that passes through Izalco volcano to the SW. The Anteojos domes, which rise only about 20-25 m above the lake surface, are mostly submerged. The southern (near) dome is andesitic, whereas the northern dome has a rhyodacitic composition. A chain of scoria cones was erupted along caldera ring faults; two of these are seen above the two domes.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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The forested island at the right is Cerro Grande (Isla la Cabra), a post-caldera lava dome on the SW side of Coatepeque caldera. The partially submerged 916-m-high rhyodacitic dome has a basal diameter of about 2.5 km and a volume of about 0.5 cu km. Small San Pedro Island (left center) is exposed during low lake levels. A fissure here reportedly erupted cinders in 1902. However, warm springs issue from the adjacent lake shore, and this event was considered by Sapper (1917) to more likely represent expulsion of water and suspended sulfur.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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The northern wall of Coatepeque caldera rises about 250 m above the surface of Lago de Coatepeque, whose shores are lined with residences and small hotels. The conical peak on the left horizon is Volcán Chingo, which straddles the El Salvador/Guatemala border. The flat-topped peak on the far right horizon is Volcán Suchitán, one of the largest volcanoes in SE Guatemala.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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Coatepeque caldera is seen here from its northern rim, with massive Santa Ana volcano in the background. Light-colored areas at the left and center are part of the caldera walls, which rise from 250 m to about one kilometer above the lake. The rounded summit behind the caldera rim at the left is Cerro Verde, which was erupted along a NW-SE-trending fissure cutting through Santa Ana.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
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Lake-filled Coatepeque caldera is prominent in this Space Shuttle image with north to the lower left. A post-caldera lava dome forms an island at the SW side of the lake. The nested summit craters of Santa Ana volcano are visible below and to the right of Coatepeque, and the unvegetated cone of Izalco volcano is to the right of Santa Ana. Small stratovolcanoes of the Sierra de Apaneca form the forested ridge at the bottom right. The light-colored area at the left-center is the city of Santa Ana, the second largest in El Salvador.

NASA Space Shuttle image ISS004-E-9398, 2002 (http://eol.jsc.nasa.gov/).
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This false color NASA aerial oblique ASTER image shows Santa Ana volcano (middle left), Izalco volcano (center), and lake-filled Coatepeque caldera from the SW. The summit of Santa Ana is truncated by a series of nested craters, and a NW-SE-trending fissure cuts across the massif. Fresh lava flows drape Izalco volcano, active from 1770 to 1966, and descend its southern flanks. The grayish area at the far upper left is the city of Santa Ana, El Salvador's second largest city.

NASA ASTER image, 2001 (http://earthobservatory.nasa.gov/Newsroom/New Images/).
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The summit crater complex of Santa Ana volcano with its small light-bluish crater lake is visible at the left-center in this false color NASA ASTER image (with north to the top). The dramatic lake-filled Coatepeque caldera cuts the eastern side of the Santa Ana massif, and Izalco volcano and its historical lava flows lie south of Santa Ana. A NW-SE-trending fissure cutting across the massif was the source of an eruption in 1722 CE from a cinder cone (center) on the SE flank that fed the lava flow seen extending across the image to the lower right.

NASA ASTER image, 2001 (http://earthobservatory.nasa.gov/Newsroom/New Images/).
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An eruption plume from Santa Ana volcano towers above Coatepeque caldera lake. The brief, one-hour-long explosive eruption the morning of October 1, 2005 produced gas-and-ash plumes that rose 10 km or more. Ash fell in towns west of the volcano and extended into Guatemala; ashfall caused damage to coffee plantations. Volcanic blocks up to a meter in diameter fell as far as 2 km south of the summit. Lahars descended valleys on the flanks of the volcano.

Photo by José Roberto Lopez, 2005 (Coatepeque Watershed Authority).
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Smithsonian Sample Collections Database


There are no samples for Coatepeque Caldera in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

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