Apaneca Range

Photo of this volcano
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 13.891°N
  • 89.786°W

  • 2036 m
    6678 ft

  • 343010
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

Most Recent Bulletin Report: November 1990 (BGVN 15:11) Citation IconCite this Report


October explosion deaths rise to 26; new crater described

The 13 October blast of steam and mud roared continuously (like a geyser) for 10-20 minutes, decreasing in intensity following the initial explosion (reported by a survivor to be around 20 seconds long). No seismic signals were recorded before or during the event by seismometers 4 and 30 km away. A portable seismometer, operated for a few days following the blast, also recorded no signals.

The 30-m-diameter, 15-m-deep crater produced by the blast was partially filled by a continuously boiling muddy lake during a 27 October visit. A sulfurous "rotten egg" smell was noted. Prior to the blast, the site was an area of steaming ground, with two small hot springs (1-2 m across) and 1 mudpot (1 m across) much smaller than the present crater.

The blast was laterally oblique to the N and its effects abruptly ended at a maximum of 130 m. Damage included downed trees and limbs, collapsed walls of buildings, and missing roofs. The massive, non-sorted deposits were clay-rich and composed of light-colored highly altered rock fragments. Deposits were thickest to the N where they ranged from 1 m on the crater rim to 30 cm at 20 m from the rim. The death toll increased to 26 after 13 people died in hospitals.

Information Contacts: C. Dan Miller, USGS.

The Global Volcanism Program has no Weekly Reports available for Apaneca Range.

Bulletin Reports - Index


Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

09/1990 (BGVN 15:09) Phreatic blast at hot springs; 14 people dead

11/1990 (BGVN 15:11) October explosion deaths rise to 26; new crater described




Information is preliminary and subject to change. All times are local (unless otherwise noted)


September 1990 (BGVN 15:09) Citation IconCite this Report


Phreatic blast at hot springs; 14 people dead

At approximately 0130 on 13 October a small phreatic blast occurred in the village of El Barro, in the SW portion of the Ahuachapán Geothermal Field. Agua Shuca (an area 2-3 m in diameter of fumaroles, mud pots, and altered ground at 13.90°N, 89.82°W) erupted violently, producing a "blast of wind, stones, and boiling water" that destroyed several small dwellings and affected an area with a 100-m radius. Fourteen people were reported killed and 21 injured [but see 15:11]. The explosion was reportedly directed and lasted about 20 seconds according to survivors. By 15 October, a quiet pond (below the boiling point), 10 m in diameter [but see 15:11], had formed in the explosion crater and the surrounding area was covered with mud.

The Ahuachapán geothermal field has been an extensively developed source of energy for more than 15 years. It is located in a highly fractured zone at the N base of Laguna Verde, an eroded stratovolcano with Pleistocene and possibly Holocene activity (figure 1). Agua Shuca is situated on a fault, 2 km S of the Ahuachapán power plant (figure 2), and is outside of the geothermal field drawdown area. A well drilled 100 m N of Agua Shuca in 1971 (AH-9), was not developed due to the low permeability of the rocks at the site. A large landslide in 1981, 1/2 km NE of Agua Shuca and along the same fault, occurred shortly after a test of the reservoir at the maximum rate of power extraction, stopped because of a dramatic pressure decline.

Figure (see Caption) Figure 1. Portion of a geologic/structural map of Ahuachapán Geothermal Field and vicinity, prepared by the Comisión Executiva Hidroeléctrica del Río Lempa. Courtesy of Dina López.
Figure (see Caption) Figure 2. Detailed structural map of the Ahuachapán Geothermal Field, prepared by the Comisión Executiva Hidroeléctrica del Río Lempa. Heavy lines mark faults, large "steaming" circles indicate hot springs, and small circles with crosses show individual geothermal wells. Courtesy of Dina López.

Information Contacts: Rodolfo Caceres, División Geotermía, Comisión Executiva Hidroeléctrica del Río Lempa, Santa Tecla, La Libertad, El Salvador; Marshall Reed, US Dept of Energy; Marcelo Lippmann, Lawrence Berkeley Laboratory, Univ of California; Grant Heiken, Los Alamos National Laboratory; Dina López, Louisiana State Univ.


November 1990 (BGVN 15:11) Citation IconCite this Report


October explosion deaths rise to 26; new crater described

The 13 October blast of steam and mud roared continuously (like a geyser) for 10-20 minutes, decreasing in intensity following the initial explosion (reported by a survivor to be around 20 seconds long). No seismic signals were recorded before or during the event by seismometers 4 and 30 km away. A portable seismometer, operated for a few days following the blast, also recorded no signals.

The 30-m-diameter, 15-m-deep crater produced by the blast was partially filled by a continuously boiling muddy lake during a 27 October visit. A sulfurous "rotten egg" smell was noted. Prior to the blast, the site was an area of steaming ground, with two small hot springs (1-2 m across) and 1 mudpot (1 m across) much smaller than the present crater.

The blast was laterally oblique to the N and its effects abruptly ended at a maximum of 130 m. Damage included downed trees and limbs, collapsed walls of buildings, and missing roofs. The massive, non-sorted deposits were clay-rich and composed of light-colored highly altered rock fragments. Deposits were thickest to the N where they ranged from 1 m on the crater rim to 30 cm at 20 m from the rim. The death toll increased to 26 after 13 people died in hospitals.

Information Contacts: C. Dan Miller, USGS.

Eruptive History


Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).


Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
[ 1990 Oct 13 ] [ Unknown ] Discredited    

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


The Ahuachapán thermal area on the NW flank of Laguna Verde has been producing geothermal power since 1975. It is one of the most recent manifestations of activity in a group of roughly E-W-trending Pleistocene and Holocene stratovolcanoes comprising the Cuyanausul Range. The Cerro El Aguila and Cerro Los Naranjos volcanoes at the eastern end of the chain are Holocene in age. No historical eruptions are known although a steam explosion from the Ahuachapán thermal area in 1990 caused fatalities.

Copyrighted photo by Dick Stoiber, 1962 (Dartmouth College).
See title for photo information.
A vapor cloud rises from well CH-D during its opening in 1996. The Ahuachapán geothermal field was the first major field to be developed in El Salvador and has been operating since 1975. The geothermal field is located mostly in permeable, highly fractured Plio-Pleistocene volcanic rocks of the San Salvador formation that are capped by a series of young pyroclastic rocks and andesitic lava flows. A younger system of NW-trending faults localizes hydrothermal features within a series of step faults dropping to the north at the margin of the Central Salvadoran Graben.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
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Two dramatic volcanoes rise above the town of Juayua (right-center) in western El Salvador. The conical peak at the left is 1961-m-high Cerro los Naranjos, one of the youngest peaks of the Apaneca Range volcanic complex. The broader peak at the right is 2365-m-high Santa Ana, El Salvador's highest volcano. Los Naranjos has not erupted in historical time, but Santa Ana has had eruptions from both summit and flank vents since the beginning of the Spanish era.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
See title for photo information.
The northern side of the broad Apaneca (Cuyanausul) Range is seen here from El Rodeo. From left to right are Cuyanausul, Laguna Verde (the sharper-topped peak at the center), Las Ninfas, and the Cerro La Cumbre/Empalizada complex. Cuyanausul and Empalizada mark the eastern and western margins, respectively, of the 6-km-wide Concepción de Ataco caldera. The E-W-trending chain of overlapping Pleistocene and Holocene stratovolcanoes of the Apaneca Range forms a major topographic barrier in western El Salvador.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
See title for photo information.
The cooling towers of the Ahuachapán-3 power plant are part of a geothermal field that has been producing for more than a quarter century. The liquid-dominated geothermal reservoir has a base temperature of about 240 degrees centigrade. It is located on the northern flank of the Apaneca (Cuyanausul) Range along the southern margin of the Salvadoran central graben. Consequently it is lower to the north and NW, where it has been affected by graben subsidence.

Photo courtesy of Comisión Ejecutiva Hidroeléctricia del Río Lempa (CEL).
See title for photo information.
Steam lines going to the power plant snake across the surface of the Ahuachapán-Chipilapa geothermal field in western El Salvador. The field is located on the northern flank of the Sierra de Apaneca range 15 km from the Guatemala border. The Ahuachapán-Chipilapa field was the first to be developed in El Salvador and began production in 1975.

Photo courtesy of Comisión Ejecutiva Hidroeléctricia del Río Lempa (CEL).
See title for photo information.
This aerial view shows the Ahuachapán-3 geothermal power plant. The Ahuachapán-Chipilapa geothermal field has an installed capacity of 95 MW and a potential of 95-150 MW. It covers an area of 200 sq km in the counties of Santa Ana, Ahuachapán, and Sonsonate. The field was the first developed in El Salvador, and the first plants came on line in 1975. During the 1980s the field was over-exploited and generated more than 40% of the country's electricity. After the reservoir pressure dropped rapidly, generation was stabilized at 48 MW.

Photo courtesy of Comisión Ejecutiva Hidroeléctricia del Río Lempa (CEL).
See title for photo information.
This view from the Apaneca Range shows the CH-A well and drill rig of the Ahuachapán geothermal field in the foreground. The conical peak on the left horizon to the north across the lowlands of El Salvador's interior valley is Volcán Chingo, along the El Salvador/Guatemala border. The flat-topped peak in the far right distance is Volcán Suchitán in Guatemala.

Photo by Comisión Ejecutiva Hidroeléctricia del Río Lempa (CEL), 1992.
See title for photo information.
La Labor fumaroles and hot pools form one of the largest thermal areas in the Ahuachapán geothermal field. The thermal area is located near the SW base of the andesitic lava dome Cerro San Lazaro about 5 km north of Laguna Verde volcano. Thermal areas of the Ahuachapán geothermal field, containing fumaroles, mud volcanoes, or hot springs, are sprinkled throughout a roughly 80 sq km area on the northern flank of the Apaneca Range.

Photo by Giuseppina Kysar, 1999 (Smithsonian Institution).
See title for photo information.
La Labor fumarole field on the flank of Laguna Verde volcano is one of the most prominent in the Ahuachapán geothermal field. The fumarole field is named for the immediately adjacent Hacienda La Labor plantation. The fumaroles typically attain temperatures of about 100 degrees centigrade. In addition to those at La Labor, fumaroles are also located at El Playón, Agua Shuca, El Sauce, and higher up at Laguna Verde and Cuyanausul, and numerous hot springs are found in the Ahuachapán geothermal area.

Photo by Giuseppina Kysar, 1999 (Smithsonian Institution).
See title for photo information.
Laguna Verde is a 500-m-wide lake that partially fills the 1-km-wide summit crater of Cerro Laguna Verde in the Apaneca Range. Laguna Verde is a 1829-m-high post-caldera stratovolcano of the Pleistocene-age Concepción de Ataco caldera. Satellitic craters on Laguna Verde volcano are among the youngest volcanic centers of the Apaneca (Cuyanausul) Range.

Photo by Giuseppina Kysar, 1999 (Smithsonian Institution).
See title for photo information.
Bubbling mudpots at La Labor fumaroles on the northern flank of Laguna Verde volcano distribute reddish oxidized mud on the surrounding boulders. This is one of several prominent fumarolic areas in the Apaneca Range. Hot springs are also found north of the Apaneca Range, particularly along the Agua Caliente and Escalante rivers.

Photo by Rick Wunderman, 1999 (Smithsonian Institution).
See title for photo information.
The Laguna Las Ninfas-Laguna Verde volcanic complex is seen here from the NW with steam plumes of the Ahuachapán geothermal field in the middle ground. The 5-km-wide Concepción de Ataco caldera was formed during the late Pleistocene following the eruption of about 70 cu km of pyroclastic flows and airfall tephra. Flat-topped Laguna Verde at the center of the photo and Las Ninfas at the right are post-caldera volcanoes. Cuyanausul stratovolcano (left horizon) was constructed prior to caldera formation and lies to the east of the caldera.

Photo by Pat Dobson, 1999 (Lawrence Berkeley National Laboratory).
See title for photo information.
Steam clouds rise above a hot pool at Agua Shuca, one of many thermal areas of the Ahuachapán geothermal field. A sudden hydrothermal explosion at Agua Shuca in October 1990 ejected clouds of steam and debris over an area of 200 m radius, and 26 people living in a small hamlet adjacent to the thermal area were killed. The Agua Shuca ("Dirty Water") thermal area ESE of Laguna Verde volcano had historically been one of the most frequently visited areas at Ahuachapán. A previous explosion apparently took place in 1868.

Photo by Pat Dobson, 1999 (Lawrence Berkeley National Laboratory).
See title for photo information.
Steam plumes rise from a test of the AH-16 production well at the Ahuachapán geothermal field. The Ahuachapán field has been producing since 1975, and in 1990 the power plant consisted of three units with a total capacity of 95 MW. The field is a high-temperature, initially water-dominated system located on the flank of Laguna Verde volcano about 2 km NW of the summit.

Photo by Pat Dobson, 1999 (Lawrence Berkeley National Laboratory).
See title for photo information.
The Apaneca Range (also known as the Cuyanausul Range) is seen here from the SE. This elongated group of roughly E-W-trending Pleistocene and Holocene stratovolcanoes lies in western El Salvador between the Santa Ana complex and the Guatemala border. The 5-km-wide Pleistocene Concepción de Ataco caldera lies beyond the flat ridge at the left; to its right are the stratovolcanoes of Cerro Cachio, Cerro de la Rana, Cerro el Aguila, and conical Cerro los Naranjos. The Apaneca Range is the site of the major geothermal field of Ahuachapán.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
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The summit of Izalco volcano provides a perspective of the adjacent Apaneca Range volcanic complex to the west. On the left horizon is flat-topped Cerro de Apaneca (also known as Chichicastepec). The city of Juayua can be seen in the center of the photo. Above it is the small peak of El Cerrito, and to its right is Cerro la Cumbre and the Cerro las Ninfas-Laguna Verde complex.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
See title for photo information.
The broad E-W-trending Apaneca Range is seen here from the south with flat-topped Cerro de Apaneca on the left. The Las Ninfas-Laguna Verde complex is in the center, and to its right are Cuyanausul, Cerro de la Rana, Cerro Aguila, and Cerro los Naranjos. The 5-km-wide Concepción de Ataco caldera lies beyond the center horizon, its rim obscured by post-caldera cones. The photo is taken from the top of a hummock on the surface of the massive Acajutla debris-avalanche deposit, which originated from Santa Ana volcano, out of view to the right.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
See title for photo information.
Flat-topped Cerro de Apaneca (also known as Chichicastepec) rises to 1831 m on the left horizon above the city of Juayua. To its right is Cerro la Cumbre and the Cerro las Ninfas-Laguna Verde complex. Construction of the latter post-dated major Pleistocene explosive eruptions that resulted in formation of the Pleistocene dacitic-rhyolitic Concepción de Ataco caldera, which lies beyond the center horizon.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
See title for photo information.
Conical Cerro los Naranjos volcano (also known as El Pilón) rises to 1961 m at the SE end of the Sierra de Apaneca. Los Naranjos is the youngest cone of the Apaneca range and at least in part postdates the late-Pleistocene collapse of ancestral Santa Ana volcano. Cerro el Aguila ("Eagle Peak") lies on the left horizon to the NW of Los Naranjos.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
See title for photo information.
The escarpment cutting diagonally downward across the middle of the photo, its face highlighted by vertical rows of trees in coffee plantations, is the NW wall of a large caldera formed by edifice collapse of Santa Ana volcano during the late Pleistocene. About 5 km of the avalanche caldera rim is exposed; the remainder is buried beneath ejecta and lava flows from modern Santa Ana volcano. Conical Cerro los Naranjos volcano rises beyond the scarp, and other peaks of the Apaneca range form the horizon on either side.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
See title for photo information.
Coffee beans dry in the sun at a finca near the town of San José la Majada in the SE part of the Apaneca range. Coffee is the primary crop in this portion of El Salvador; rich volcanic soil and abundant rainfall provide excellent habitat for coffee trees that blanket the flanks of the volcanoes of the Apaneca range and Santa Ana massif. The Cerro las Ninfas-Laguna Verde complex forms the ridge on the center-to-right horizon.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
See title for photo information.
The escarpment cutting diagonally downward across the middle of the photo in front of conical Cerro los Naranjos volcano is the NW wall of a large late-Pleistocene caldera formed by edifice collapse of Santa Ana volcano. The exposed portion of the collapse scarp is up to about 200 m high along a roughly 5 km segment of the arcuate avalanche caldera. Pyroclastic ejecta and lava flows from modern Santa Ana volcano have filled in much of the scarp in the foreground and have buried it completely on the northern and eastern sides.

Photo by Paul Kimberly, 2002 (Smithsonian Institution).
See title for photo information.
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/).
See title for photo information.

Smithsonian Sample Collections Database


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

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