SANTA ANA El Salvador 13.853°N, 89.630°W; summit elev. 2,365 m; All times are local (= UTC - 6 hours) Reports from 2001: | January | Reports from 2005: | August | September | Santa Ana Information from the SI/USGS Global Volcanism Program -------------------------------------------------------------------------------- 17-23 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's Volcano Disaster Assistance Program, Washington VAAC, US Geological Survey's National Earthquake Information Center, La Prensa Grafica, Diario del Hoy 1/19/01, Diario del Hoy 1/12/01 -------------------------------------------------------------------------------- 24-30 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) -------------------------------------------------------------------------------- 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) -------------------------------------------------------------------------------- 7-13 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) -------------------------------------------------------------------------------- 14-20 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) -------------------------------------------------------------------------------- 21-27 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)