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Izalco

Photo of this volcano
  • El Salvador
  • México and Central America
  • Stratovolcano
  • 1966 CE
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 13.813°N
  • 89.633°W

  • 1950 m
    6398 ft

  • 343030
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

Most Recent Bulletin Report: December 1999 (BGVN 24:12) Citation IconCite this Report

Fumaroles active 35 years ago now emitting water vapor at 86°C

Izalco's summit crater was visited to examine the fumarole field that was the site of many geochemical and mineralogical studies in the 1960's and 1970's. The remaining fumaroles consist only of water vapor with a maximum temperature of 86°C.

Volcan de Izalco originated in 1770 A.D. on the S flank of Santa Ana volcano. Frequent Strombolian eruptions from the volcano, known as the "Lighthouse of Central America," produced a 650-m-high stratovolcano within 200 years.

Information Contacts: Alain Bernard, BRUGEL, Université Libre de Bruxelles 160/02 50, Ave. Roosevelt, 1050 Brussels, Belgium.

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

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.

02/1974 (CSLP 21-74) Thermal anomaly detected in 1973

02/1999 (BGVN 24:02) Strong fumarolic activity around the summit crater

12/1999 (BGVN 24:12) Fumaroles active 35 years ago now emitting water vapor at 86°C




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


February 1974 (CSLP 21-74)

Thermal anomaly detected in 1973

Card 1792 (07 February 1974) Thermal anomaly detected in 1973

Remote infrared thermal patterns have been measured on the northeast flank . . . four times since December 1969. The sensor station is on Cerro Cerde at a distance of 1,100 m from Izalco. On 7 July 1973, a thermal anomaly appeared near the summit in a region that had been thermally inactive in earlie infrared studies. The anomaly stretched downslope about 50 m and covered an area about 1,000 m2. The highest of the anomalous apparent surface etemperatures was 15°C, 2° above ambient. Data just processed from the 24 November 1973 observations show the anomaly expanded to the east to cover about 5,000 m2. The most intense apparent surface temperatures occur in the same spot as the earlier pattern and register 19°C, 8° above ambient. The anomaly was intensified. The appearance and intensification of a thermal anomaly at Izalco indicates a change in the thermal regime of the volcano. The temperatures of the summit fumaroles were not unusually high in December 1973. The concentration of intermediate-depth earthquakes just south of Izalco was unusually high for the period 1971-72, as compared to 1967-70. Geophysical observations of these anomalous events are continuing.

Izalco last erupted in October-November 1966, with a lava flow from its south flank. Prior to that it had undergone intermittent lava and pyroclastic eruptions from 1770 to 1956, building up a composite cone 650 m above its base.

Information Contacts: Richard Birnie, Harvard University, Cambridge, MA; Ian Lange, Department of Geology, University of Montana, Missoula, MT; R. E. Stoiber, Department of Earth Sciences, Dartmouth College, Hanover, NH.


February 1999 (BGVN 24:02) Citation IconCite this Report

Strong fumarolic activity around the summit crater

During fieldwork on Santa Ana volcano in February, increased steaming was observed at the summit of Izalco relative to levels of previous years. Strong fumarolic activity occurred along the entire circumference of the 250-m-wide summit crater, with the exception of the NE side facing Cerro Verde. Activity was most vigorous at a vent on the N side of the crater floor, but was also strong along much of the inner rim of the crater and along its outer flanks. Steaming was observed over broad areas on the outer southern flanks to ~50 m below the rim, and on the W flank immediately N of a shoulder of the cone at ~1,800 m elevation, roughly 150 m below the summit. Activity had earlier been noticed to have increased in November 1998 following Hurricane Mitch. Most of the steaming was water vapor, and the increased activity was attributed to saturation of the still-warm cone by heavy rains accompanying the hurricane.

Information Contacts: Carlos Pullinger, Calle Padres Aguilar 448, Colonia Escalon, San Salvador, El Salvador; Demetrio Escobar, Centro de Investigaciones Geotecnicas (CIG), Final Blvd. Venezuela y calle a La Chacra, Apdo. Postal 109, San Salvador, El Salvador; Lee Siebert and Paul Kimberly, Global Volcanism Program, Smithsonian Institution.


December 1999 (BGVN 24:12) Citation IconCite this Report

Fumaroles active 35 years ago now emitting water vapor at 86°C

Izalco's summit crater was visited to examine the fumarole field that was the site of many geochemical and mineralogical studies in the 1960's and 1970's. The remaining fumaroles consist only of water vapor with a maximum temperature of 86°C.

Volcan de Izalco originated in 1770 A.D. on the S flank of Santa Ana volcano. Frequent Strombolian eruptions from the volcano, known as the "Lighthouse of Central America," produced a 650-m-high stratovolcano within 200 years.

Information Contacts: Alain Bernard, BRUGEL, Université Libre de Bruxelles 160/02 50, Ave. Roosevelt, 1050 Brussels, Belgium.

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 54 Holocene eruptive periods.

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1966 Oct 28 1966 Nov 16 ± 15 days Confirmed 0 Historical Observations SSE flank (550 m below summit)
1948 Nov 4 1957 Dec 1 ± 30 days Confirmed 3 Historical Observations Summit, SW and NE flanks
1939 Feb 1948 Feb Confirmed 2 Historical Observations Summit and SSE flank
1937 (?) 1938 (?) Confirmed 2 Historical Observations
1933 Nov 30 1934 Jan 12 (in or after) Confirmed 2 Historical Observations
1931 Mar 31 ± 90 days Unknown Confirmed 2 Historical Observations
1930 Apr Unknown Confirmed 0 Historical Observations Outer slope of eastern summit crater
1927 1928 (?) Confirmed 2 Historical Observations
1925 Dec 26 1927 Jan Confirmed 3 Historical Observations
1924 Mar Unknown Confirmed 2 Historical Observations
1920 Oct 29 1921 Apr 10 Confirmed 2 Historical Observations SE flank
1912 Jan 16 1916 Jan 26 Confirmed 2 Historical Observations Summit and NE flank
1903 Nov 1905 Mar Confirmed 2 Historical Observations Summit and east flank
1902 May 10 1902 Dec 30 Confirmed 2 Historical Observations Summit and NE flank
1899 Dec 31 1900 Mar Confirmed 2 Historical Observations
1891 1898 Jul Confirmed 2 Historical Observations
1890 Mar 26 ± 5 days 1890 Apr 20 Confirmed 0 Historical Observations Summit and upper east flank
1887 1889 Confirmed 2 Historical Observations
1885 Unknown Confirmed 2 Historical Observations
1884 Mar 9 1884 Mar 10 Confirmed 2 Historical Observations
1883 Sep 5 ± 4 days 1883 Nov 13 Confirmed 2 Historical Observations
1882 Jul 12 Unknown Confirmed 2 Historical Observations
1881 Jan 1 Unknown Confirmed 0 Historical Observations
1879 Dec 25 1880 Mar Confirmed 2 Historical Observations
1878 Unknown Confirmed   Historical Observations
[ 1874 ] [ 1875 ] Uncertain    
1872 Dec 1873 Mar 19 (in or after) Confirmed 2 Historical Observations
[ 1870 May 19 ] [ Unknown ] Uncertain 2  
1869 Mar 1 (?) 1869 Jun 18 (in or after) Confirmed 2 Historical Observations Summit and east flank
1868 Feb 16 1868 Feb 17 Confirmed 2 Historical Observations
1867 Apr 1867 Aug Confirmed 2 Historical Observations
1866 Apr 27 1866 Aug 15 ± 5 days Confirmed 2 Historical Observations
1864 May 15 ± 2 days 1865 Jun 15 ± 5 days Confirmed 2 Historical Observations Summit and NE flank
1863 Unknown Confirmed 0 Historical Observations
1859 Dec 8 1860 Jan 22 Confirmed 0 Historical Observations
1858 Feb 6 1859 Jul Confirmed 2 Historical Observations
1857 Feb 15 1857 Feb 19 (in or after) Confirmed 2 Historical Observations
1856 May 24 1856 Sep 1 ± 1 days Confirmed 2 Historical Observations Summit and south flank
1854 May 13 1854 Jun 8 Confirmed 2 Historical Observations
1850 Unknown Confirmed 2 Historical Observations
1844 Jun 1844 Oct Confirmed 2 Historical Observations
1842 Unknown Confirmed 2 Historical Observations
1838 1840 Confirmed 2 Historical Observations
1836 Unknown Confirmed 2 Historical Observations
1825 Unknown Confirmed 2 Historical Observations
1817 Unknown Confirmed 2 Historical Observations
1805 1807 Confirmed 2 Historical Observations
1802 1803 Confirmed 2 Historical Observations
1798 Apr Unknown Confirmed 2 Historical Observations
1793 Mar 29 1793 Sep Confirmed 2 Historical Observations
1783 Jul (?) Unknown Confirmed 0 Historical Observations
1772 (?) Unknown Confirmed 2 Historical Observations
1770 Feb 23 Unknown Confirmed 2 Historical Observations
[ 1636 ] [ Unknown ] Discredited    
Deformation History

There is no Deformation History data available for Izalco.

Emission History

There is no Emissions History data available for Izalco.

Photo Gallery

Volcán de Izalco is seen here from the north, on the southern flank of Santa Ana. It began erupting in 1770 CE and frequent Strombolian eruptions produced a steep-sided, 650-m-high stratovolcano over a 200-year period. Izalco was one of the most frequently active volcanoes in Central America, producing ejecta and lava flows from both summit and flank vents.

Copyrighted photo by Stephen O'Meara.
This aerial view shows Izalco with south at the top of the photo. The cone was constructed during frequent eruptions over a two-century period beginning in 1770. Strombolian eruptions from the summit crater were sometimes accompanied by lava flows that traveled down the flank to the south, extending as far as 7 km from the summit.

Copyrighted photo by Stephen O'Meara.
The broad Santa Ana volcano is to the right, with Izalco volcano to the left in this NW-looking view from the Zapotitán basin. The cone in the center is Cerro Verde, and the smaller, low-profile scoria cone below it is Cerro Marcelino. Historical eruptions have occurred from the summit crater of Santa Ana and flank cones such as Cerro Marcelino to the SE. Izalco formed in 1770, and the saddle between Izalco and Cerro Verde increased 100 m in height in the century after 1866.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
Volcán Izalco is one of El Salvador's most well-known volcanoes. It rises more than 1 km above its southern base (left) and 300 m above the saddle between it and Cerro Verde, a flank cone on Santa Ana (right). Since Izalco began erupting in 1770, the summit grew about 650 m above its original vent on the flank of Santa Ana volcano.

Photo by Paul Kimberly, 1999 (Smithsonian Institution).
Izalco volcano was once known as the "Lighthouse of the Pacific" for its persistent incandescent nighttime eruptions. It was constructed on the southern flank of Santa Ana, whose broad summit is to the left. To the right is Cerro Verde, a scoria cone on the SE Santa Ana flank. Lava flows at the base if Izalco from both summit and flank vents and extend out to 7 km.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
A lava flow field on the SW flank of Izalco is seen here from its summit. Levees define distinct flows of the lava field, which extends up to about 7 km from the summit. Most of the flows seen here were emplaced prior to 1954. Gas rises from fumaroles near the summit.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
The lava flows with levees in the center of the photo were extruded from a vent on the NE flank of Izalco beginning in 1955. This lava extrusion took place during an almost continuous period of Strombolian activity from November 1948 until the end of 1957. Periods of lava effusion took place July 1950, September-November 1952, October 1954, intermittently in 1955, November 1956, and January 1957. The eruption tapered off in late 1957 and was over by the end of the year.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
Izalco has been one of El Salvador's most active volcanoes during historical time. More than 50 eruptions took place since it began to erupt in 1770, many lasting several years to about a decade in duration. Eruptions took place both from the summit craters and from flank vents. Unvegetated lava flows are seen here on the SE flank below Cerro Verde (center) and El Conejal and El Astillero (right).

Photo by Paul Kimberly, 1999 (Smithsonian Institution).
Santa Ana rises beyond the Izalco summit crater, which began erupting in 1770 on the northern Santa Ana flank. Fumarolic activity continues at Izalco, producing the faint steam plume in the right foreground, but has diminished considerably since the 200-year-long eruptive period ended in 1966. A complex of four nested craters gives the summit of Santa Ana a flat profile. The flank of Cerro Verde is seen to the right.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
A vertical aerial photo shows the unvegetated slopes and dark-colored lava flows of Volcán de Izalco, El Salvador's youngest volcano. It originated in 1770 CE on the southern flank of Santa Ana volcano, whose summit lies to the north (top). Steep-sided, 650-m-high Izalco stratovolcano is truncated by a 250-m-wide crater. The flanks of Izalco consist primarily of pyroclastic material erupted from the summit crater; lava flows mostly originated from vents on the lower flanks and were deflected southward by the slopes of Santa Ana volcano.

Aerial photo by Instituto Geográfico Nacional El Salvador, 1996.
The flanks of Izalco volcano contrast with the vegetated Cerro Verde in the foreground. Izalco rises about 300 m above the saddle separating it from Cerro Verde. This view shows the Pacific Ocean 40 km to the south with much of the area between underlain by deposits associated with a late-Pleistocene Santa Ana debris avalanche.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
Three peaks of the Santa Ana massif can be seen from the highway between Sonsonate and San Salvador. The summit of Santa Ana volcano is to the left, the unvegetated Izalco volcano is to the right, and between them is Cerro Verde.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
A lava flow field is at the base of Izalco composed of flows that mostly erupted from flank vents. They were deflected by the flank of Santa Ana and extend as far as about 7 km from the Izalco summit. The vegetated Cerro Verde scoria cone is to the right and is part of a trend of cones and vents that erupted SE of Santa Ana.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
Izalco grew to its present height during a 200-year period since it began erupting in 1770 at an elevation of about 1,300 m on the flank of Santa Ana. Intermittent Strombolian eruptions and the effusion of dominantly basaltic-andesite lava flows built up the volcano so that by the year 1866 the summit was at 1,825 m elevation, by 1866 it was at 1,825 m, by 1892 it was at 1,885 m, by 1951 it was at 1,900 m, by 1953 it was at 1,935, and by 1956 it was at 1,965 m.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
Izalco towers above the western flanks of Santa Ana, which are covered in coffee crops. Izalco erupted in a cornfield on the southern flanks of Santa Ana in 1770 and grew 650 m above the vent over the following two centuries. Despite its proximity to Santa Ana, Izalco lavas are distinctly higher in aluminum, calcium, and strontium. Recent eruptions of Izalco are more similar to Santa Ana than earlier ones.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
Izalco volcano rises beyond the Cerro Verde flank to the left, as seen from the trail to the summit of Santa Ana. Hotel de la Montaña was constructed at the summit of Cerro Verde to provide a view of the Izalco erupting, which occurred frequently since 1770. By the time the hotel was completed, the eruption of Izalco had ended.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
This false-color oblique DEM overlain by a thermal infrared ASTER image shows Santa Ana volcano (middle left), Izalco volcano (center), and the roughly 5.5 x 6 km Coatepeque caldera lake from the SW. The summit of Santa Ana has series of nested craters, and a NW-SE-trending fissure across the edifice. Lava flows were recently emplaced across the southern flanks of Izalco. The grayish area at the far upper left is the city of Santa Ana, El Salvador.

NASA ASTER image, 2001 (https://earthobservatory.nasa.gov/).
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 ASTER satellite image (N is to the top; this image is approximately 30 km across). The lake-filled Coatepeque caldera is east of Santa Ana, and Izalco volcano with its lava flows are to the south. A fissure was the source of an eruption in 1722 CE from a scoria cone (center) on the SE flank that produced the lava flow across the image to the lower right.

NASA ASTER image, 2001 (https://earthobservatory.nasa.gov/).
GVP Map Holdings

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. The maps database originated over 30 years ago, but was only recently updated and connected to our main database. We welcome users to tell us if they see incorrect information or other problems with the maps; please use the Contact GVP link at the bottom of the page to send us email.


Title: Bath of Gulf of Mexico & Caribbean Sea
Publisher: AAPG, Williams & Heintz Map Corp.
Country: US/ C.Am/ S.Am
Year: 1984
Map Type: Bathymetric
Scale: 1:3,289
Map of Bath of Gulf of Mexico & Caribbean Sea

Title: Belize, El Salvador, Guatemala, Honduras, Mexico
Publisher: DMA Aerospace Center
Country: NW C Am (GU ES HO)
Year: 1982
Series: TPC
Map Type: Topographic
Scale: 1:500,000
Map of Belize, El Salvador, Guatemala, Honduras, Mexico
Smithsonian Sample Collections Database

The following 9 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections, and may be availble for research (contact the Rock and Ore Collections Manager). Catalog number links will open a window with more information.

Catalog Number Sample Description Lava Source Collection Date
NMNH 144942-00 Stoiberite -- --
NMNH 145722-00 Stoiberite -- --
NMNH 160385-00 Bannermanite -- --
NMNH 160387-00 Fingerite -- --
NMNH 163183-00 Mcbirneyite -- --
NMNH 164270-00 Blossite -- --
NMNH 164470-00 Lyonsite -- --
NMNH 165494-00 Howardevansite -- --
NMNH 165495-00 Howardevansite -- --
External Sites