Santa Ana

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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 13.853°N
  • 89.63°W

  • 2381 m
    7810 ft

  • 343020
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

29 March-4 April 2006

During 24-31 March, activity at Santa Ana decreased to low levels in comparison to the previous 4 months of moderate activity. During the report period, seismicity was at relatively low levels, steam plumes occasionally rose ~200 m above the volcano (or 8,400 ft a.s.l.), and the daily sulfur-dioxide flux was between 500 and 1,000 metric tons. The Alert Level remained at red, the highest level, within 5 km of the volcano's summit crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)



 Available Weekly Reports


2006: January | February | March
2005: August | September | October | November | December
2001: January


29 March-4 April 2006

During 24-31 March, activity at Santa Ana decreased to low levels in comparison to the previous 4 months of moderate activity. During the report period, seismicity was at relatively low levels, steam plumes occasionally rose ~200 m above the volcano (or 8,400 ft a.s.l.), and the daily sulfur-dioxide flux was between 500 and 1,000 metric tons. The Alert Level remained at red, the highest level, within 5 km of the volcano's summit crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


1 March-7 March 2006

During 24 February to 6 March, seismicity at Santa Ana was relatively stable, and the sulfur-dioxide flux was lower than during previous weeks. The level of water in the lagoon within the crater decreased significantly. The Alert Level at Santa Ana remained at Red, the highest level, within a 5-km radius around the volcano's summit crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


22 February-28 February 2006

During 17-24 February, volcanic activity was at moderate levels at Santa Ana. Seismicity was relatively stable, and steam plumes rose to low levels above the volcano. The sulfur-dioxide flux was similar to measurements from previous weeks. The level of water in the lagoon within the crater decreased significantly. The Alert Level at Santa Ana remained at Red, the highest level, within a 5-km radius around the volcano's summit crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


8 February-14 February 2006

During 3-10 February, volcanic activity was at moderate levels at Santa Ana. Seismicity was relatively stable, and steam plumes rose to low levels above the volcano. The sulfur-dioxide flux averaged 1,200 metric tons per day. The Alert Level at Santa Ana remained at Red, the highest level, within a 5-km radius around the volcano's summit crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


1 February-7 February 2006

During 27 January- 3 February, volcanic activity was at moderate levels at Santa Ana. On the 2nd, there was an increase in seismicity at the volcano, possibly related to an earthquake on the coast of Guatemala. There was also an increase in the sulfur-dioxide flux, with an average of 2,000 metric tons measured daily. Steam plumes rose to low levels above the volcano. The Alert Level at Santa Ana remained at Red, the highest level, within a 5-km radius around the volcano's summit crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


18 January-24 January 2006

Seismicity at Santa Ana during 14-20 January 2006 was at normal levels. Degassing continued, with sporadic gas-and-steam emissions that rose about 200 m before dispersing. Sulfur dioxide flux, measured 6 km SW of the volcano, ranged from 163 to 1,578 metric tons/day. The hazard status remained at Alert Red, the highest level, within a 5-km radius of the central crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


11 January-17 January 2006

During 6-13 January, volcanic activity was moderate at Santa Ana. Seismicity was a bit over normal levels with small earthquakes occurring, which were interpreted as being associated with gas pulses. Continuous low-level emissions of steam and gas originated from the lagoon and from fumaroles within the crater. The sulfur-dioxide flux ranged between 544 and 2,300 metric tons per day. The Alert Level remained at Red, the highest level, within a 5-km radius around the volcano's summit crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


4 January-10 January 2006

During 30 December to 6 January, volcanic activity was moderate at Santa Ana. Seismicity was a bit over normal levels with small earthquakes occurring, which were interpreted as being associated with gas pulses. Continuous low-level emissions of steam and gas originated from the lagoon and from fumaroles within the crater. Gas rose 200-500 m above the crater (or 8,400-9,400 ft a.s.l.) and drifted SW. The sulfur-dioxide flux ranged between 180 and 1,476 metric tons per day. The Alert Level remained at Red, the highest level, within a 5-km radius around the volcano's summit crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


28 December-3 January 2006

Observations of Santa Ana's crater on 28 December revealed that there were continuous emissions of steam and gas from the lagoon and fumaroles located within the crater. Gas rose 200-500 m above the crater (or 8,400-9,400) and drifted SW. On 30 December, seismicity at Santa Ana was above background levels. Small earthquakes occurred, which were interpreted as being associated with gas pulses. Gas emissions rose to low levels. The Alert Level remained at Red, the highest level, within a 5-km radius around the volcano's summit crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


21 December-27 December 2005

During 21-23 December, seismicity at Santa Ana was above background levels. Small earthquakes occurred, which were interpreted as being associated with gas pulses. Gas emissions rose to low levels. The Alert Level remained at Red, the highest level, within a 5-km radius around the volcano's summit crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


14 December-20 December 2005

During 14-20 December, seismicity at Santa Ana was above background levels. Small earthquakes occurred, which were interpreted as being associated with gas pulses. Gas emissions rose to low levels. The Alert Level remained at Red, the highest level, within a 5-km radius around the volcano's central crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


7 December-13 December 2005

Seismic activity began to increase at Santa Ana on 26 November. At that time, hundreds of metric tons of sulfur dioxide were emitted from the volcano each day, which was not as high as levels measured prior to the 1 October eruption. Gas emissions rose to ~300 m above the volcano and only slight changes were noted in the color of the lagoon in the interior of the crater. SNET stated that the high level of activity indicated that an eruption could occur in the following days. During 7-12 December, activity was still at high levels. The Alert Level remained at Red, the highest level, within a 5-km-radius around the volcano's central crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


23 November-29 November 2005

During 23-28 November, seismicity at Santa Ana was above background levels. Small earthquakes occurred that were interpreted as being associated with gas pulses. The amount of gas emitted was low. The Alert Level remained at Red, the highest level, within a 5-km radius around the volcano's central crater.

Source: Servicio Nacional de Estudios Territoriales (SNET)


16 November-22 November 2005

During 16-21 November seismicity at Santa Ana was above background levels; a minor increase on 17 November was probably due to strong wind disturbing the seismic equipment. Small earthquakes occurred that were interpreted as being associated with the fracturing of rocks and gas pulses. The amount of gas emitted was low. The daily sulfur-dioxide flux averaged about 1,000 metric tons during 11-17 November. The Alert Level within a 5-km radius around the volcano's central crater remained at Red, the highest level.

Source: Servicio Nacional de Estudios Territoriales (SNET)


9 November-15 November 2005

During 9-14 November, seismicity at Santa Ana was above background levels and slightly increased on 13 November. Small earthquakes occurred that were interpreted as being associated with the fracturing of rocks and gas pulses. The amount of gas emitted was low. The sulfur-dioxide flux ranged between 100 and 1,200 metric tons daily. The Alert Level within a 5-km radius around the volcano's central crater remained at Red, the highest level.

Source: Servicio Nacional de Estudios Territoriales (SNET)


2 November-8 November 2005

During 2-7 November, seismicity and volcanic activity remained at relatively low levels at Santa Ana. Small earthquakes occurred that were associated with the fracturing of rocks and gas pulses. Sulfur-dioxide emissions were low, with 100 to 200 metric tons recorded daily. Gas emissions rose to low levels above the volcano. The Alert Level within a 5-km radius around the volcano's central crater remained at Red, the highest level.

Source: Servicio Nacional de Estudios Territoriales (SNET)


26 October-1 November 2005

During 30-31 October, seismicity increased at Santa Ana. Volcanic activity appeared to slightly increase starting on 28 October. Sulfur-dioxide emission rates during 28 and 29 October averaged 257 metric tons per day. The Alert Level within a 5-km radius around the volcano's central crater was at Red, the highest level.

Source: Servicio Nacional de Estudios Territoriales (SNET)


19 October-25 October 2005

During 19-23 October, seismicity was relatively stable and there were low-level gas emissions at Santa Ana. On 22 October, a lahar was reactivated in the Potrero Arriba area, NE of the volcano. During 22-25 October, there was an increase in the amount of tremor at the volcano. In addition, seismicity associated with gas emissions slightly increased. The Alert Level within a 5-km radius around the volcano's central crater was at Red, the highest level.

Source: Servicio Nacional de Estudios Territoriales (SNET)


12 October-18 October 2005

During 12-17 October, seismicity was relatively stable and there were low-level gas emissions at Santa Ana. Storms on 12 October caused the generation of lahars that traveled towards Coatepeque.

Source: Servicio Nacional de Estudios Territoriales (SNET)


5 October-11 October 2005

During 5-11 October, small explosions, degassing, and low-to-moderate seismicity occurred at Santa Ana. Inclement weather during much of the report period prohibited ground and satellite observations and sulfur-dioxide measurements. During an aerial inspection of the volcano on 11 October, no changes were observed at the crater. Around the 11th, sulfur-dioxide measurements were at 600-700 metric tons per day. SNET noted that eruptive activity could continue at the volcano and an eruption similar to, or smaller than, the October 1 eruption could occur in the future. The Alert Level within a 5-km radius around the volcano's central crater was at Red, the highest level.

Source: Servicio Nacional de Estudios Territoriales (SNET)


28 September-4 October 2005

SNET reported that a sudden eruption at Santa Ana (also called Ilamatepec) on 1 October around 0820 produced an ash-and-gas plume to a height of ~10 km above the volcano (or 40,600 ft a.s.l.). According to the Washington VAAC, ash was visible on satellite imagery at a height of ~14 km (46,000 ft) a.s.l. Ash fell in towns W of the volcano, including in Naranjos, Nahuizalco, Juayúa, Ahuachapán, and La Hachadura. Volcanic blocks up to a meter in diameter fell as far as 2 km S of the volcano's crater. Lahar deposits were seen SE of the volcano. The Alert Level within a 4-km radius around the volcano's central crater was raised to Red, the highest level. According to news reports, two people were killed by landslides (possibly caused by heavy rain in the area) in the town of Palo Campana, and thousands of residents near the volcano were evacuated. As many as 1,400 hectares of crops were damaged by ash.

Prior to the eruption, significant changes in seismicity were not noted. On 3 October, after the eruption, seismicity fluctuated and small explosions occasionally occurred. Earthquakes associated with explosions were recorded. In addition, there was a decrease in the amount of sulfur dioxide emitted from the volcano. SNET noted that eruptive activity could continue at the volcano.

Sources: Servicio Nacional de Estudios Territoriales (SNET), Reuters, Associated Press, ReliefWeb


21 September-27 September 2005

During 21-26 September, seismicity and gas emissions were above normal levels at Santa Ana as they had been since 27 July. Microseismicity remained at relatively high levels. During the report period, gas plumes rose to a maximum height of ~1 km above the volcano (or 11,000 ft a.s.l.) on 26 September. During a visit to the crater on 21 September, observers noted that the summit crater lagoon had become greener and small rock slides occurred in a fumarolic area. Santa Ana remained at Alert Level Yellow Phase 1.

Source: Servicio Nacional de Estudios Territoriales (SNET)


14 September-20 September 2005

During 15-19 September, seismicity and gas emissions were above normal levels at Santa Ana as they had been since 27 July. Microseismicity remained at relatively high levels. During the report period, gas plumes rose to ~500 m above the volcano (or 9,400 ft a.s.l.) and the sulfur-dioxide flux reached a maximum of 3,320 metric tons per day on 16 September. No significant changes were seen at the volcano's crater when observed on 19 September in comparison to 13 September. Intense degassing continued and the lagoon remained a "dark coffee" color. Incandescence was visible inside some cracks. Santa Ana remained at Alert Level Yellow Phase 1.

Source: Servicio Nacional de Estudios Territoriales (SNET)


7 September-13 September 2005

During 7-12 September, seismicity and gas emissions were above normal levels at Santa Ana as they had been since 27 July. Microseismicity increased significantly on 12 September. During a visit to the volcano on 8 September, larger areas of incandescence were visible at a field of fumaroles than during a visit on 29 August. During the report period, gas plumes rose to ~500 m above the volcano (or 9,400 ft a.s.l.) and the sulfur-dioxide flux was over 1,000 metric tons per day. Satellite imagery showed a thermal anomaly at the volcano on several days. Santa Ana remained at Alert Level Yellow Phase 1.

Source: Servicio Nacional de Estudios Territoriales (SNET)


31 August-6 September 2005

During 1-6 September, seismicity and gas emissions were above normal levels at Santa Ana as they had been since 27 July. Tremor continued to be recorded, and on 2 August a cluster of at least eight small earthquakes occurred. The earthquakes were not felt by local residents. During the report period, gas plumes rose to ~500 m above the volcano (or 9,400 ft a.s.l.) and the sulfur-dioxide flux was over 1,000 metric tons per day. Satellite imagery from 5 September showed a thermal anomaly at the volcano. Santa Ana remained at Alert Level Yellow Phase 1.

Source: Servicio Nacional de Estudios Territoriales (SNET)


24 August-30 August 2005

SNET reported a significant increase in seismic activity at Santa Ana (also called Ilamatepec) on the night of 27 August. A cluster of 17 volcano-tectonic earthquakes were recorded, with four located S of the volcano. Afterwards, continuous high-frequency tremor was recorded until at least 30 August. Observations made on 29 August revealed incandescent rocks in the fumarole field. The incandescence was due to the hot gases emitted from the fumaroles heating the rocks. A significant increase in sulfur-dioxide emission was recorded, and gas-and-steam plumes rose 500-1,000 m above the volcano's crater (or 9,400-11,000 ft a.s.l.). As a safety measure, access to the volcano's crater was restricted to visitors.

Prior to the current increase in activity, strong degassing had been measured at the volcano since June 2004. An ash emission occurred on 16 June 2005, and a slight increase in seismicity and a significant increase in gas emission was measured from 27 July until at least 30 August.

Source: Servicio Nacional de Estudios Territoriales (SNET)


17 January-23 January 2001

Beginning on 12 January several news reports stated that increased volcanic activity occurred at Santa Ana volcano. The Washington VAAC reported that an eruption occurred at 1800 on 16 January that sent ash to ~3.7 km a.s.l. Local observations by volcanologists revealed that an eruption did not occur and no new lava or magma was in the summit crater. Glowing cracks that were visible at night were determined to be an existing fumarole field with measured temperatures of 550 °C. Scientists believe that a magnitude 7.7 earthquake that occurred off the coast of Central America at 1133 on 13 January, killing several hundred people, did not cause an increase in activity at the volcano. Since 12 January there have been reports of increased gas emissions and the volcano is being closely monitored for any changes in activity.

Sources: US Geological Survey Volcano Disaster Assistance Program (VDAP), Washington Volcanic Ash Advisory Center (VAAC), US Geological Survey Earthquake Hazards Program, La Prensa Grafica, Diario del Hoy


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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2005 Jun 16 2005 Oct 1 (?) Confirmed 3 Historical Observations
[ 1920 Nov ] [ Unknown ] Uncertain 2  
1904 Jan 12 1904 Jan 26 (?) Confirmed 2 Historical Observations
1884 Mar 9 1884 Mar 10 Confirmed 2 Historical Observations
[ 1882 ] [ Unknown ] Uncertain    
1880 Mar Unknown Confirmed 3 Historical Observations NW flank (Mala Cara)
1879 Feb 1 ± 30 days Unknown Confirmed 2 Historical Observations
[ 1878 ] [ Unknown ] Uncertain 2  
1874 Unknown Confirmed 3 Historical Observations
1734 Jun (in or before) Unknown Confirmed 2 Historical Observations
1722 Mar 12 Unknown Confirmed 2 Historical Observations SE flank (San Marcelino)
[ 1650 ± 50 years ] [ Unknown ] Discredited    
[ 1621 ] [ Unknown ] Uncertain    
1576 Unknown Confirmed 3 Historical Observations
1570 (?) Unknown Confirmed   Historical Observations
1524 Apr 30 ± 30 days Unknown Confirmed 3 Historical Observations
1521 Dec 31 ± 365 days Unknown Confirmed 3 Historical Observations
[ 1520 ] [ Unknown ] Uncertain    

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Bernard A, Escobar C D, Mazot A, Gutierrez R E, 2004. The acid volcanic lake of Santa Ana volcano, El Salvador. In: Rose W I, Bommer J J, Lopez D L, Carr M J, Major J J (eds), Natural Hazards in El Salvador, {Geol Soc Amer Spec Pap}, 375: 121-133.

Carr M J, 1984. Symmetrical and segmented variation of physical and geochemical characterisitics of the Central American volcanic front. J Volc Geotherm Res, 20: 231-252.

Carr M J, Pontier N K, 1981. Evolution of a young parasitic cone towards a mature central vent; Izalco and Santa Ana volcanoes in El Salvador, Central America. J Volc Geotherm Res, 11: 277-292.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

Mooser F, Meyer-Abich H, McBirney A R, 1958. Central America. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 6: 1-146.

Pullinger C, 1998. Evolution of the Santa Ana volcanic complex, El Salvador. Unpublished MSci thesis, Michigan Tech Univ, 151 p.

Rodriquez L A, Watson M W, Rose W I, Branan Y K, Bluth G J S, Chigna G, Matias O, Escobar D, Carn S A, Fischer T P, 2004. SO2 emissions to the atmosphere from active volcanoes in Guatemala and El Salvador, 1999-2002. J Volc Geotherm Res, 138: 325-344.

Sapper K, 1925. The Volcanoes of Central America. Halle: Verlag Max Niemeyer, 144 p.

Scolamacchia T, Pullinger C, Caballero L, Montalvo F, Beramendi Orosco L E, Gonzalez Hernandez G, 2010. The 2005 eruption of Ilamatepec (Santa Ana) volcano, El Salvador. J Volc Geotherm Res, 189: 291-318.

Siebert L, Kimberly P, Pullinger C R, 2004. The voluminous Acajutla debris avalanche from Santa Ana volcano, western El Salvador, and comparison with other Central American edifice-failure events. In: Rose W I, Bommer J J, Lopez D L, Carr M J, Major J J (eds), Natural Hazards in El Salvador, {Geol Soc Amer Spec Pap}, 375: 5-23.

Williams H, Meyer-Abich H, 1955. Volcanism in the southern part of El Salvador with particular reference to the collapse basins of Lakes Coatepeque and Ilopango. Univ Calif Pub Geol Sci, 32: 1-64.

Santa Ana, El Salvador's highest volcano, is a massive, 2381-m-high, dominantly andesitic-to-trachyandesitic stratovolcano that rises immediately west of Coatepeque caldera. Collapse of Santa Ana (also known as Ilamatepec) during the late Pleistocene produced a voluminous debris avalanche that swept into the Pacific Ocean, forming the Acajutla Peninsula. Reconstruction of the volcano subsequently filled most of the collapse scarp. The broad summit of the volcano is cut by several crescentic craters, and a series of parasitic vents and cones have formed along a 20-km-long fissure system that extends from near the town of Chalchuapa NNW of the volcano to the San Marcelino and Cerro la Olla cinder cones on the SE flank. Historical activity, largely consisting of small-to-moderate explosive eruptions from both summit and flank vents, has been documented since the 16th century. The San Marcelino cinder cone on the SE flank produced a lava flow in 1722 that traveled 13 km to the east.