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Ilopango

Photo of this volcano
  • Country
  • Volcanic Region
  • Landform | Volc Type
  • Last Known Eruption
  • 13.672°N
  • 89.053°W

  • 450 m
    1,476 ft

  • 343060
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports available for Ilopango.

The Global Volcanism Program has no Weekly Reports available for Ilopango.

The Global Volcanism Program has no Bulletin Reports available for Ilopango.

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.

Eruptive History

There is data available for 2 confirmed Holocene eruptive periods.

1879 Dec 31 - 1880 Mar 26 ± 5 days Confirmed Eruption VEI: 3

Episode 1 | Eruption Islas Quemadas, Lake Ilopango
1879 Dec 31 - 1880 Mar 26 ± 5 days Evidence from Observations: Reported
 Following severe earthquakes 20-31 December 1879, the water level in Lake Ilopango rose over 6-11 January 1880, accompanying growth of the Islas Quemadas lava dome. By 9 January discharge down the Jiboa River was strong enough to flood the valley, destroying the town of Atuscatla and killing many cattle. A huge column of ash and incandescent rocks was observed on 20 January and the dome breached the surface on 23 January; three periods of dome growth accompanied by explosions ensued. The dome reached a height of 50 m above the lake before explosions 5 March destroyed most of the subaerial portion. CAVW considers the onset of seismicity on 31 December 1879 to mark the onset of dome growth and notes that the eruption ended in late March.

List of 8 Events for Episode 1 at Islas Quemadas, Lake Ilopango

Start Date End Date Event Type Event Remarks
1879 Dec 20 1879 Dec 31 Seismicity (volcanic) Before eruption.
1879 Dec 31    - - - - Seismicity (volcanic)
1880 Jan 6    - - - - Lava dome
1880 Jan 9    - - - - Fauna Kill Terrestrial.
1880 Jan 9    - - - - Property Damage
1880 Jan 20    - - - - Explosion
1880 Jan 20    - - - - VEI (Explosivity Index) VEI 3
1880 Mar 5    - - - - Explosion Explosions destroyed most of the subaerial portion of the lava dome.

0450 ± 30 years Confirmed Eruption VEI: 6

Episode 1 | Eruption Tierra Blanca Joven
0450 ± 30 years - Unknown Evidence from Isotopic: 14C (calibrated)
 The massive Tierra Blanca eruption (14C dated 260 ± 114 CE) destroyed early Mayan cities and resulted in the formation of the Ilopango Caldera (Sheets, 1979). AMS radiocarbon dating combined with careful analysis of previous dates provided a weighted age of 1605 ± 20 yrs BP (Dull et al., 2001). This has a 2-sigma calendar age of 408-536 CE, with the probability distribution weighted toward the early part of this range, between 415 and 476 CE. Dull et al. (2001) noted evidence for sudden evacuation of archaeological sites over broad areas after about 400 CE, and Sheets (2004) estimated 30,000 fatalities within the area swept by pyroclastic flows. The 71 km3 airfall tephra volume (Kutterolf et al., 2008) does not include the unknown volume of pyroclastic flows.

List of 12 Events for Episode 1 at Tierra Blanca Joven

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion extremely violent or catastrophic
   - - - -    - - - - Pyroclastic flow
   - - - -    - - - - Ash
   - - - -    - - - - Lapilli
   - - - -    - - - - Bombs
   - - - -    - - - - Blocks
   - - - -    - - - - Pumice
   - - - -    - - - - Caldera Explosion
   - - - -    - - - - Property Damage
   - - - -    - - - - Evacuations
0450 ± 30 years    - - - - Fatalities
0450 ± 30 years    - - - - VEI (Explosivity Index)
Deformation History

There is no Deformation History data available for Ilopango.

Emission History

There is no Emissions History data available for Ilopango.

Photo Gallery

The 8 x 11 km Ilopango caldera, filled by one of El Salvador's largest lakes, has a scalloped 150-500 m high rim. The caldera, seen here from its west rim, is strongly controlled by regional faults of the central Salvador graben. Its latest collapse resulted from the massive 5th century CE Tierra Blanca eruption that produced widespread pyroclastic flows and devastated early Mayan cities. The latest of a series of post-caldera eruptions formed the Islas Quemadas, a group of low islets in the center of the lake, in 1879-1880.

Photo by Kristal Dorion, 1994 (U.S. Geological Survey).
The SW wall of Ilopango caldera rises about 500 m above the surface of the caldera lake. Punta La Peninsula (center) on the western side of the caldera extends a kilometer into the lake. The high wall on the southern side of the lake is a fault scarp in southward-dipping rocks of the Pliocene Balsamo formation. The scenic lake is a popular resort destination from the capital city of San Salvador, and the shores of the lake are dotted with resorts and vacation homes.

Photo by Kristal Dorion, 1994 (U.S. Geological Survey).
Ilopango caldera is seen in this aerial view from the SW with San Vicente stratovolcano to the right. The latest collapse of the 13 x 17 km caldera occurred after a powerful eruption during 536-550 CE that produced widespread pyroclastic flows and devastated early Mayan cities. The caldera now contains a lake with lava domes forming small islands near the shore and near its center.

Copyrighted photo by Stephen O'Meara.
Volcanologist Jim Vallance samples the TB3 (Tierra Blanca 3) deposit, the second oldest of four major deposits associated with the formation of Ilopango caldera. This outcrop is located south of the town of Panchimalco, about 20-30 km SW of the caldera.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
The 13 x 17 km Ilopango caldera is filled by one of El Salvador's largest lakes. The caldera, which has a scalloped 150-500 m high rim, lies immediately east of the capital city of San Salvador (upper left). The latest caldera collapse event occurred during the massive 536-550 CE eruption, which produced widespread pyroclastic flows and devastated early Mayan cities. Post-caldera eruptions formed a series of lava domes within the lake and near its shore.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
Four major pyroclastic units associated with the incremental formation of Ilopango caldera are exposed in this quarry. The Tierra Blanca (White Soil) unit that was emplaced over much of central and western El Salvador consists of (from bottom to top) the Pleistocene TB4 (the orange-colored unit at the base), TB3, and TB2 units (separated by thin soils), and the Holocene TBJ unit. The latter is called the Tierra Blanca Joven (the young Tierra Blanca) and was erupted about 1,500 years ago. Note the geologist on the left side of the outcrop for scale.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
Geologists investigate an outcrop of the Tierra Blanca Joven (TBJ) formation about 10 km SE of Ilopango caldera where it originated. The TBJ was produced during the last of four major explosive eruptions that formed the caldera and deposited pyroclastic flows, ashfall, and pumice across much of central and western El Salvador. The eruption destroyed early Mayan cities and forced their abandonment for decades to centuries. Trade routes were disrupted, and the centers of Mayan civilization shifted from the highland areas of El Salvador to lowland areas to the north and in Guatemala.

Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).
The 13 x 17 km Ilopango caldera is seen here from the NE with the southern caldera wall in the background. It formed during four major Quaternary eruptions, the last of which occurred about 1,500 years ago. The southern caldera wall rises about 500 m above the lake, which had a maximum depth of about 230 m when this photo was taken in 1999.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
Lake Ilopango occupies the Ilopango caldera immediately east of the capital city of El Salvador, seen in the foreground. This view is from San Salvador volcano with San Vicente volcano in the background. The caldera formed during four major eruptions, the last of which was about 1,500 years ago. This eruption deposited ash and pumice over much of central and western El Salvador.

Photo by Paul Kimberly, 1999 (Smithsonian Institution).
Pyroclastic flow and ashfall deposits from Ilopango caldera, known collectively as Tierra Blanca (White Soil), are found over much of central and western El Salvador. This quarry near the city of Cojutepeque (9 km ENE of the caldera) exposes the Tierra Blanca Joven (TBJ) formation that was produced during the youngest of several Tierra Blanca eruptions about 1,500 years ago. The eruption destroyed early Mayan cities and resulted in their abandonment for decades to centuries.

Photo by Giuseppina Kysar, 1999 (Smithsonian Institution).
The western side of Lake Ilopango is seen from the southern rim of Ilopango caldera. The broad peak on the right-hand horizon is the Pleistocene Guazapa volcano. The northern wall of Ilopango caldera rises about 400-500 m above the lake. Much of the caldera rim contains thick caldera-forming eruption deposits, and some lava domes are exposed in the caldera wall.

Photo by Bill Rose, 1978 (Michigan Technological University).
The SW corner of Ilopango caldera is visible in the foreground with the outskirts of the capital city of San Salvador behind it. The high peak on the left horizon (NW) is El Picacho, part of the San Salvador volcanic complex, a recently active volcano overlooking the capital city. Below it to the left is San Jacinto, a Pliocene lava dome complex. The broad peak in the background to the right is the Pliocene Cerro Nejapa volcano.

Photo by Bill Rose, 1978 (Michigan Technological University).
The two tiny islands in the center of Lake Ilopango barely visible above the house in the foreground are the Islas Quemadas. These are post-caldera lava domes that were emplaced from 31 December 1879 to March 1880. A huge ash plume with incandescent ejecta were erupted on 20 January and the dome breached the lake surface on 23 January. It reached a height of 50 m above the lake surface before violent explosions on 5 March destroyed most of the visible part of the dome.

Photo by Bill Rose, 1978 (Michigan Technological University).
The 8 x 11 km wide Ilopango caldera fills the center of the image in this view from the ESE. Fresh, light-colored exposures of the Tierra Blanca Joven formation in the foreground associated with the latest caldera-forming episode were in part created by landslides during the January 2001 earthquake. The capital city of San Salvador lies beyond the lake, in front of San Salvador volcano (upper right). The Santa Ana volcanic complex lies beyond San Salvador volcano in the background to the far right.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
GVP Map Holdings

Maps are not currently available due to technical issues.

The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included.

Smithsonian Sample Collections Database

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

External Sites