Galeras

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  • 1.22°N
  • 77.37°W

  • 4276 m
    14025 ft

  • 351080
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15 May-21 May 2013

INGEOMINAS reported that during 15-21 May seismicity at Galeras was at a low level; during 19-20 May earthquakes with magnitudes 2.6 or less were concentrated in an area 3 km SW at depths near 4 km. Gas plumes rose 500 m above the crater and contained small amounts of ash during 15-16 and 20-21 May. Sulfur dioxide emissions were low. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)



 Available Weekly Reports


2013: April | May
2012: January | May | June | July | August | September | October
2011: January | February | March | November | December
2010: February | August
2009: January | February | March | April | May | June | July | September | October | November | December
2008: January | September | October | November | December
2007: March | October | November | December
2006: January | February | March | April | May | June | July | December
2005: January | February | May | June | July | August | November | December
2004: July | August | September | October | November


15 May-21 May 2013

INGEOMINAS reported that during 15-21 May seismicity at Galeras was at a low level; during 19-20 May earthquakes with magnitudes 2.6 or less were concentrated in an area 3 km SW at depths near 4 km. Gas plumes rose 500 m above the crater and contained small amounts of ash during 15-16 and 20-21 May. Sulfur dioxide emissions were low. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


10 April-16 April 2013

INGEOMINAS reported that during 10-16 April earthquakes at Galeras were located in various areas as far as 13 km from the crater, at depths no greater than 14 km and with maximum magnitudes of 2. Moderate levels of sulfur dioxide were detected; plumes drifted NW. Cameras recorded ash emissions all week, especially on 9, 11, 12, and 14 April, when pulsating activity produced plumes that drifted W. Plumes rose no more than 1 km above the crater. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


31 October-6 November 2012

INGEOMINAS reported that during 30 October-6 November seismicity at Galeras fluctuated but was slightly lower compared to the previous week. Sulfur dioxide gas emissions were low. Cameras around Galeras recorded gas-and-ash plumes rising from the crater on 30 October and 1 November. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


24 October-30 October 2012

INGEOMINAS reported that during 24-30 October cameras around Galeras recorded daily emissions, including pulsating ash emissions. Multiple gas-and-ash plumes rose 500 m above the crater on 25 and 27 October. Seismicity fluctuated but was slightly lower compared to the previous week. Sulfur dioxide gas emissions were low to moderate. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


17 October-23 October 2012

INGEOMINAS reported that during 17-23 October cameras around Galeras recorded daily emissions. On 19 and 21 October the plumes contained ash and rose 1.8 km above the crater. On 19 October observatory staff reported fine ashfall on the NE flank and a sulfur odor was reported in Consacá Sandoná (W flank). Staff at the Galeras National Park Wildlife Sanctuary reported sulfur odors on the E side of the volcano. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


10 October-16 October 2012

INGEOMINAS reported that during 9-16 October cameras around Galeras recorded daily emissions; on 9 and 12 October ash was present in the emissions in small quantities. On 12 October a gas-and-ash plume rose 1 km above the crater, and staff at the Galeras National Park Wildlife Sanctuary reported sulfur gas odor in a cabin located on the E side of the volcano. Earthquakes were at most M 1.7 and occurred within 10 km of the crater at depths of less than 6 km. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


3 October-9 October 2012

INGEOMINAS reported that during 2-9 October cameras around Galeras recorded daily emissions that drifted NW and often contained ash. Earthquakes were at most M 2.2 and occurred within 15 km of the crater at depths of less than 10 km. An M 2.2 earthquake on 8 October was located at a depth of 8 km, 7 km NE of the crater. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


26 September-2 October 2012

INGEOMINAS reported that during 25 September-2 October cameras around Galeras recorded emissions that were mostly water vapor drifting NW. However, on 27 and 28 September the emissions contained ash. An earthquake swarm detected on 28 September was characterized by M 1.4 events that occurred within 13 km of the crater at depths less than 8 km. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


19 September-25 September 2012

INGEOMINAS reported that during 18-22 and 24-25 September cameras around Galeras recorded emissions that were mostly water vapor. On 18 and 24 September the emissions contained ash. An earthquake swarm detected on 25 September was characterized by events less than M 1 that occurred 2 km W of the crater at depths near 3 km. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


22 August-28 August 2012

INGEOMINAS reported that during 21-28 August seismicity at Galeras increased. Sulfur dioxide emissions fluctuated, but remained at low-to-moderate levels. Cameras around the volcano recorded emissions during 21-26 August; the emissions contained ash on 26 August. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


15 August-21 August 2012

INGEOMINAS reported that both earthquake occurrence and magnitude were low at Galeras during 14-21 August. Sulfur dioxide emissions fluctuated, but remained at moderate levels. An ash plume rose from the crater on 16 August. White plumes were observed during 16 and 18-21 August. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


8 August-14 August 2012

INGEOMINAS reported that during 8-14 August seismicity at Galeras continued to be elevated. Some of the earthquakes were located near the active cone, with magnitudes less than 1 and depths not exceeding 2 km. During 7-9 and 11 August gas-and-ash plumes rose 0.9-1.3 km above the crater and drifted W and S. Sulfur dioxide emissions fluctuated between moderate and high levels. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


1 August-7 August 2012

INGEOMINAS reported that during 31 July-6 August the magnitude and occurrence of earthquakes detected at Galeras had increased since the previous week. Gas plumes sometimes containing tephra rose from the crater. Observatory staff working near the crater reported a strong sulfur odor on 1 and 6 August. On 3 August a steam plume rose 1.1 km above the crater. On 4 August ash emissions were observed in the morning, and at 1519 a seven-minute-long episode of tremor was accompanied by a gas-and-ash plume that rose 1.4 km above the crater and drifted N. Ashfall was reported in Genoy, 6 km NE. An ash plume rose from the crater on 7 August. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


18 July-24 July 2012

INGEOMINAS reported that during 18-24 July earthquakes at Galeras were less than M 1.3 and located at depths not exceeding 3 km. Gas emissions, observed by a network of video cameras, contained ash almost daily. Sulfur dioxide levels fluctuated. On 18 July observatory staff working near the crater reported a strong sulfur odor and fine ash falling on the upper N flank. Ashfall was also reported to the N in the Quebrada Maragato area (municipality of Nariño). The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


4 July-10 July 2012

INGEOMINAS reported that during 4-10 July seismicity at Galeras indicated continuing gas emissions; sulfur dioxide levels were moderate. The emissions, observed by a network of video cameras, contained some ash during 4-5 July. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


20 June-26 June 2012

INGEOMINAS reported that during 20-26 June the magnitude of earthquakes detected at Galeras had decreased since the previous week, but seismicity continued to indicate ash and gas emissions. During 19-22 and 24 June cameras recorded gas-and-ash emissions that drifted NW. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


13 June-19 June 2012

INGEOMINAS reported that during 5-19 June seismicity at Galeras had increased in both magnitude and frequency since the previous week-long period, and indicated continuing ash and gas emissions. On 5, 6, and 12-19 June cameras recorded gas-and-ash emissions; an ash plume rose 1.4 and 2.4 km above the crater on 14 and 17 June, respectively. Ashfall was reported in Sandona (13 km NW), Samaniego (32 km NW), Mapachico (8 km NW), and Genoy (5 km NE). Sulfur dioxide emissions were moderate to high. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


6 June-12 June 2012

On 5 June INGEOMINAS reported that seismicity at Galeras increased since the previous week and indicated continuing ash and gas emissions. Ash originated from an area N and W of the cone within the main crater and was emitted in a pulsating manner. Ash was deposited on the NW flanks. Ash emissions were especially frequent on 2 and 5 June, with plumes rising 1 km above the crater. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


30 May-5 June 2012

INGEOMINAS reported that on 17 May ash emissions originating from an area N and W of the cone within Galeras's main crater rose 200 m above the crater rim. During 26-27 May ash plumes rose 800 m above the crater; ashfall was reported in Sandona (13 km NW). Ash emissions occurred on 2 June, and on 5 June plumes rose 1 km and drifted W. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Sources: Washington Volcanic Ash Advisory Center (VAAC), Servicio Geológico Colombiano (SGC)


4 January-10 January 2012

INGEOMINAS reported that low-level activity continued at Galeras during 4-10 January, with steam rising from the main crater and two craters to the N and SW (Paisita and Chavas, respectively). The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


28 December-3 January 2012

INGEOMINAS reported that activity continued at Galeras during 28 December- 3 January, with steam rising from the main crater and two craters to the N and SW (Paisita and Chavas, respectively). A web camera showed gas emissions on 28, 30, and 31 December and on 1 January. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


21 December-27 December 2011

INGEOMINAS reported that activity continued at Galeras during 21-27 December, with steam rising from the main crater and two craters to the N and SW (Paisita and Chavas, respectively). The Alert Level remains at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


14 December-20 December 2011

INGEOMINAS reported that activity continued at Galeras during 14-20 December, with steam rising from the main crater and two craters to the N and SW (Paisita and Chavas, respectively). The Alert Level remains at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


7 December-13 December 2011

INGEOMINAS reported that activity continued at Galeras during 7-13 December, with steam rising from the main crater and two craters to the N and SW (Paisita and Chavas, respectively). On 9 and 11 December earthquakes of M 2.3 and 2.5, felt by local residents, occurred near the crater at a depth of 1.5 km. The Alert Level remains at III (Yellow; "changes in the behavior of volcanic activity"). olcanic activity").

Source: Servicio Geológico Colombiano (SGC)


30 November-6 December 2011

INGEOMINAS reported that observations of Galeras during an overflight on 29 November revealed thermal analomies in the main crater. During an overflight on 6 December scientists observed that gas emissions rose from the main crater and two craters to the N and SW (Paisita and Chavas, respectively) and had increased in comparison to the previous week. Thermal anomalies were also detected in the main crater. INGEOMINAS raised the Alert Level to III (Yellow; "changes in the behavior of volcanic activity") on 6 December.

Source: Servicio Geológico Colombiano (SGC)


23 November-29 November 2011

INGEOMINAS reported that during 15-22 November steam from Galeras rose from the main crater, two craters to the N and SW (Paisita and Chavas, respectively), and a crack on the N flank of the active cone. Seismicity was at low levels, although some earthquakes were characterized as "tornillo-type." During 23-24 November the seismic network detected an emerging seismic pattern of "tornillo-type" earthquakes similar to patterns detected prior to past eruptions. Gas emissions also decreased. INGEOMINAS raised the Alert Level to II (Orange; "probable eruption in term of days or weeks") on 24 November.

Source: Servicio Geológico Colombiano (SGC)


30 March-5 April 2011

INGEOMINAS reported that on 31 March and 1 April emissions from Galeras were characterized by gas-and-steam plumes with low ash content. On 1 April a M 2.3 earthquake occurred 3 km E of the crater at a depth of 6 km and was felt by nearby residents. During an overflight on 2 April scientists noted a sulfur gas odor and observed that gas emissions rose from multiple areas of the active cone. During 30 March-5 April, sulfur dioxide gas values were between 50 and 2,000 tons per day, the latter value was considered high for Galeras. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


2 February-8 February 2011

On 8 February, INGEOMINAS reported that "tornillo-type" earthquakes from Galeras had not been detected since 5 February. Seismic levels continued to fluctuate. On 6 February an overflight revealed that gas emissions had increased in comparison to the previous week, forming plumes that drifted NW. The Alert Level was lowered to III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


26 January-1 February 2011

INGEOMINAS reported that on 25 January an emerging seismic pattern from Galeras, characterized by "tornillo-type" earthquakes, was similar to patterns detected prior to past eruptions. Staff noted a strong sulfur gas odor and observed emissions from various areas of the crater that drifted N. Based on changes in seismicity and observed gas emissions, INGEOMINAS raised the Alert Level to II (Orange; "probable eruption in term of days or weeks"). Scientists again observed emissions from various areas of the crater during an overflight on 27 January, but with a slight increase in the number of vents. Gas plumes drifted NW. "Tornillo-type" earthquakes ceased on the morning of 30 January.

Source: Servicio Geológico Colombiano (SGC)


25 August-31 August 2010

An eruption from Galeras that began at 0400 on 25 August prompted INGEOMINAS to raise the Alert Level to I (Red; "imminent eruption or in progress"). Meteorological cloud cover initially prevented visual observations of the summit. Seismicity associated with the eruption continued for a period of about 12 hours and gradually declined in the afternoon. The Alert Level was lowered to II (Orange; "probable eruption in term of days or weeks"). Scientists aboard an overflight later that day observed ash-and-gas emissions from multiple areas of the active cone, and thermal anomalies that were detected on the N side of the cone. Ash fell to the NW, as far away as 30 km. According to news articles, about 7,000 were requested by officials to evacuate, although few left their homes. During 26-31 August at least 12 earthquakes, M 2-4, were located within a 2-km radius from the crater, at depths not more than 3 km. Gas plumes drifted NW, then S.

Sources: Servicio Geológico Colombiano (SGC), CNN


18 August-24 August 2010

INGEOMINAS reported that an earthquake swarm from Galeras which began on 20 August had been preceded by increased gas emissions a few days prior. During 21-22 August seismicity remained high. Five volcano-tectonic earthquakes were felt by local residents and caused windows to vibrate. They were located within a 300-900 m radius from the crater, at depths of less than 2 km. The largest event was M 4.3. On 23 August a M 4.6 earthquake was located E of Galeras at a depth of 2 km. The Alert Level was raised to II (Orange; "probable eruption in term of days or weeks"). An eruption began on 25 August, prompting INGEOMINAS to raise the Alert Level to I (Red; "imminent eruption or in progress"). Meteorological cloud cover initially prevented visual observations of the summit, although an eruption plume was seen amongst the clouds, and thermal anomalies were detected by an infrared camera. Ashfall was reported in areas 7-12 km NW. Observers in Pasto (~ 10 km E) reported that gas-and-ash plumes rose 300 m above the crater.

Source: Servicio Geológico Colombiano (SGC)


3 February-9 February 2010

On 9 February, INGEOMINAS lowered the Alert Level for Galeras to III (Yellow; "changes in the behavior of volcanic activity"). During the previous few days, seismicity was low and sulfur dioxide emissions were low to moderate.

Source: Servicio Geológico Colombiano (SGC)


30 December-5 January 2010

An explosive eruption from Galeras detected by the seismic network on 2 January prompted INGEOMINAS to raise the Alert Level to I (Red; "imminent eruption or in progress"). An ash plume rose to an altitude of 12 km (39,400 ft) a.s.l. and drifted W and NW. Ashfall was reported in areas downwind, as far away as 110 km W. Ejected incandescent blocks fell onto the flanks 3.2-3.5 km away from the summit and ignited fires. An overflight on 3 January revealed diffuse gas plumes from the main crater. Fires started the previous day continued to burn on the N flank. The Alert Level was lowered to II (Orange; "probable eruption in term of days or weeks").

Source: Servicio Geológico Colombiano (SGC)


9 December-15 December 2009

INGEOMINAS reported that observations of Galeras during an overflight on 3 December revealed thermal anomalies in the main crater measuring 155 degrees Celsius. During 8-11 December, seismic activity decreased, although some seismic signals resembled patterns seen prior to previous eruptions. Sulfur dioxide emissions were low. Seismicity increased on 12 December; earthquakes M 2.2 and less were detected within 2 km of the summit and at depths up to 3 km below the summit during 12-15 December. The Alert Level was raised to II (Orange; "probable eruption in term of days or weeks").

Source: Servicio Geológico Colombiano (SGC)


25 November-1 December 2009

On 27 November, INGEOMINAS lowered the Alert Level for Galeras to III (Yellow; "changes in the behavior of volcanic activity"). During the previous few days, seismicity was low and occasionally punctuated by signals indicative of minor gas and ash emissions. An overflight on 26 November revealed gas emissions from the interior walls of the main crater and thermal anomalies with temperatures of 200 degrees Celsius. During 27 November-1 December, seismicity remained low; signals indicated gas emissions.

Source: Servicio Geológico Colombiano (SGC)


18 November-24 November 2009

An explosive eruption from Galeras detected by the seismic network on 20 November prompted INGEOMINAS to raise the Alert Level to I (Red; "imminent eruption or in progress"). Residents reported five explosions, sound waves, and incandescence from multiple areas in the crater. Plume modelling from the Washington VAAC suggested that the resulting ash plume may have risen as high as 14.3 km (46,900 ft) a.s.l. and drifted N. Ashfall was reported in areas 10 km E, N, and NNW. Seismicity increased after the eruption and then gradually decreased. On 21 November, INGEOMINAS lowered the Alert Level to II (Orange; "probable eruption in term of days or weeks"). According to news articles, 900-1,000 people out of about 9,000 ordered to evacuate went to shelters.

Sources: Servicio Geológico Colombiano (SGC), Agence France-Presse (AFP)


11 November-17 November 2009

INGEOMINAS reported that an overflight of Galeras on 14 November revealed thermal anomalies in the main crater measuring 110 degrees Celsius and very low rates of gas discharge. The Alert Level remained at II (Orange; "probable eruption in term of days or weeks").

Source: Servicio Geológico Colombiano (SGC)


4 November-10 November 2009

INGEOMINAS reported that during 7-10 November seismic activity from Galeras decreased, although some seismic signals resembled patterns seen prior to previous eruptions. Sulfur dioxide emissions were not detected. The Alert Level remained at II (Orange; "probable eruption in term of days or weeks").

Source: Servicio Geológico Colombiano (SGC)


28 October-3 November 2009

On 30 October, INGEOMINAS reported that the Alert Level for Galeras was raised to II (Orange; "probable eruption in term of days or weeks"). Since 27 October, degassing decreased and seismicity increased, reflecting conditions seen prior to previous eruptions. On 3 November, INGEOMINAS stated that gas emissions had been low during the previous days, and seismicity had decreased that day.

Source: Servicio Geológico Colombiano (SGC)


30 September-6 October 2009

An explosive eruption from Galeras on 30 September prompted INGEOMINAS to raise the Alert Level to I (Red; "imminent eruption or in progress"). National Park personnel reported two explosions and incandescent material ejected from the area of the active cone. An ash plume rose to an approximate altitude of 12.3 km (40,400 ft) a.s.l. and drifted E, then N. The sulfur dioxide emission rate was between 1,100 and 9,300 tons per day. Ash was deposited in Sandoná (15 km NW), and Ancuya, Linares, and Sotomayor (40 km NW). Seismicity decreased after the eruption. On 1 October, seismicity was low and the sulfur dioxide emission rate was 300 tons per day. The Alert Level was lowered to II (Orange; "probable eruption in term of days or weeks"), and then to III (Yellow; "changes in the behavior of volcanic activity") on 6 October.

Source: Servicio Geológico Colombiano (SGC)


29 July-4 August 2009

On 4 August, INGEOMINAS reported that activity from Galeras had remained at a low level since the previous report on 28 July; the Alert Level was lowered to III (Yellow; "changes in the behavior of volcanic activity"). During the previous few days, active fumaroles were seen on the W flank of the active cone.

Source: Servicio Geológico Colombiano (SGC)


24 June-30 June 2009

INGEOMINAS reported that during 22-23 June gas plumes rising from Galeras contained some ash. An overflight on 23 June revealed that temperatures in the main crater measured between 60 and 120 degrees Celsius, except for a small zone where the temperature measured 220 degrees Celsius. Gas emissions originated from the periphery of the main crater. On 26 June, seismicity similar to that seen prior to previous eruptions, along with low rates of gas emissions, prompted INGEOMINAS to raise the Alert Level to II (Orange; "probable eruption in term of days or weeks").

Source: Servicio Geológico Colombiano (SGC)


17 June-23 June 2009

Increased sulfur-dioxide degassing and seismicity related to fluid movement, resulting in the overall lowering of pressure in the system, prompted INGEOMINAS to further lower the alert level to Yellow (Level III) on 19 June. By 23 June some rock-fracture seismicity had been detected, though events related to fluid movement had declined significantly. That same day clear weather allowed observation of a small gas column with minor ash content, while scientists on a monitoring flight saw gas emissions near the crater rim and recorded a thermal anomaly within the main crater.

Source: Servicio Geológico Colombiano (SGC)


10 June-16 June 2009

On 10 June, INGEOMINAS reported that the Alert Level for Galeras was lowered to II (Orange; "probable eruption in term of days or weeks"). Pulsating steam plumes rose from the crater and drifted NW. Seismicity remained low.

Source: Servicio Geológico Colombiano (SGC)


3 June-9 June 2009

INGEOMINAS reported that an eruption of Galeras on 7 June was preceded by a M 4 earthquake located about 3 km SSE of the crater at a depth of 2 km, and felt by nearby residents. The eruption produced an ash plume that rose to an altitude of 6.8 km (22,300 ft) a.s.l. and drifted NW. Vibrations from an accompanying acoustic wave were detected by residents. Ashfall was reported in areas downwind. The Alert Level was raised to I (Red; "imminent eruption or in progress"). On 8 June, two explosions about 5 minutes apart were heard by people up to 45 km away. The event was preceded by an M 3.9 earthquake located 1 km E at a depth near 2 km. Ashfall was reported in areas to the NW, up to 180 km away. Based on analysis of satellite imagery, the Washington VAAC reported that the ash plume rose to an altitude of 10 km (33,000 ft) a.s.l. and drifted NW. They also reported that a second and larger eruption produced an ash plume that rose to an altitude of 13.7 km (45,000 ft) a.s.l. and drifted SE. On 9 June, INGEOMINAS reported that seismicity and sulfur dioxide output were low, and that clear conditions revealed no emissions.

Sources: Servicio Geológico Colombiano (SGC), Washington Volcanic Ash Advisory Center (VAAC)


13 May-19 May 2009

On 19 May, INGEOMINAS reported that gas plumes from Galeras occasionally contained some ash during the previous four days. An overflight on 17 May revealed gas emissions emanating from multiple points inside and outside of the main crater. Some thermal anomalies surpassed 180 degrees Celsius. During 17-18 May, two M 2.9 earthquakes occurred 6 km SSE at depths of 2-3 km, and on 18 May one M 2.3 earthquake occurred at a depth of 3-5 km, 5 km SSW. The Alert Level was lowered to III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


6 May-12 May 2009

On 6 May, INGEOMINAS reported that gas-and-ash plumes from Galeras rose to an altitude of 5.8 km (19,000 ft) a.s.l. and drifted NE. An overflight revealed incandescence from a vent, 90-100 m in diameter, in the main crater that corresponded to a 500 degree Celsius temperature anomaly. Blocks, 9-13 m in diameter, scattered on the S and SE flanks were part of the 2008 lava dome that had been ejected during the 24 April 2009 eruption. White plumes originated from multiple points inside and outside of the crater. Volcanic tremor seldom occurred during the previous week. The Alert Level was lowered to III (Yellow; "changes in the behavior of volcanic activity").

On 9 May, a M 2.2 volcano-tectonic earthquake occurred 6 km to the NE of the main crater at a depth of 10 km. On 11 May, seismicity increased, and hybrid earthquakes and tremor were detected. The recent seismicity, along with incandescence in the crater, and low sulfur dioxide values suggested to INGEOMINAS that the volcano may become overpressurized. The Alert Level was raised to II (Orange; "probable eruption in term of days or weeks"). Steam plumes rose 250 m and drifted NW on 12 May.

Source: Servicio Geológico Colombiano (SGC)


29 April-5 May 2009

INGEOMINAS reported that on 29 April an eruption from Galeras was detected by the seismic network. Observers to the N and NW reported that an ash plume drifted NW; ash fell in areas up to 35 km downwind. During 4-5 May, ash plumes drifted NE and ashfall was reported in multiple areas of Pasto (about 10 km E). The Alert Level remained at II (Orange; "probable eruption in term of days or weeks").

Source: Servicio Geológico Colombiano (SGC)


22 April-28 April 2009

INGEOMINAS reported that on 24 April seismicity from Galeras was similar to that seen prior to previous eruptions. Video camera views of the crater showed decreased gas emissions. The Alert Level was raised to II (Orange; "probable eruption in term of days or weeks"). Later that day, an explosive eruption was detected, prompting INGEOMINAS to raise the Alert Level to I (Red; "imminent eruption or in progress"). Incandescent blocks caused fires on the N flank. An accompanying shock wave was reported by residents up to 25 km away. A second eruption, of greater duration but less energy than the first, was detected about a half an hour later. Incandescence from both eruptions was seen from the city of Pasto (10 km E). An ash plume rose to an altitude of 10.3 km (33,800 ft) a.s.l. Ashfall was reported in areas up to 20 km W, WNW, and NW. According to a news article, populations living near the volcano were ordered to evacuate; about 200 people responded. On 25 April, ash-and-gas plumes rose 1 km above the crater. Thermal anomalies in the crater near the W flank measured 100 degrees Celsius. Ejected rocks had landed 2-3 km from the crater. The Alert Level was lowered to II.

Sources: Servicio Geológico Colombiano (SGC), Colombia Reports


1 April-7 April 2009

INGEOMINAS reported that pulsating gas plumes from Galeras, sometimes containing ash, were seen when weather allowed during 3-7 April and rose to altitudes less than 6 km (19,700 ft) a.s.l. Overflights on 5, 6, and 7 April revealed that the emissions came from different areas in the main crater. Zones of high temperatures (180 degrees Celsius) were noted; an incandescent area measured 500 degrees Celsius on 7 April. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


18 March-24 March 2009

On 24 March, INGEOMINAS lowered the Alert Level for Galeras to III (Yellow; "changes in the behavior of volcanic activity"). During the previous week daily sulfur dioxide levels were high. Earthquake levels were low in both intensity and occurrence. During 21-23 March, white-colored gas plumes rose to an altitude of 5.4 km (17,700 ft) a.s.l. and drifted in multiple directions.

Source: Servicio Geológico Colombiano (SGC)


11 March-17 March 2009

INGEOMINAS reported an explosive eruption from Galeras that began at 1555 on 13 March; the Alert Level was raised from II (Orange; "probable eruption in term of days or weeks") to I (Red; "imminent eruption or in progress"), on a scale of 4-1. Inclement weather prevented direct observations of the volcano. The Washington Volcanic Ash Advisory Center (VAAC) indicated that a plume rose to an altitude of 12.3 km (40,400 ft) a.s.l. and drifted NW. The eruption produced sounds heard in areas 10 km E and W. Ashfall was reported in multiple areas E and NW; a sulfur odor was also reported in some areas. On 14 March, gas plumes with some ash content rose to an altitude of 6.3 km (20,700 ft) a.s.l. The Alert Level was lowered to back to II.

According to news articles, authorities ordered the evacuation of about 8,000 people living in high-risk areas, but few went to evacuation shelters.

Sources: Servicio Geológico Colombiano (SGC), El Tiempo


4 March-10 March 2009

INGEOMINAS reported that on multiple occasions during 6-10 March white gas plumes from Galeras were occasionally tinged gray or brown and rose to altitudes less than 6.3 km (21,000 ft) a.s.l. An estimated 2 million cubic meters of material, or about 40 percent of the volume of the lava dome, was deposited during the eruptions that took place on 14 and 20 February. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


25 February-3 March 2009

INGEOMINAS reported that on several occasions during 25 February-2 March white gas plumes from Galeras with variable ash content rose to a peak altitude of 5.4 km (17,700 ft) a.s.l. and drifted NNW. On 3 March, the Alert Level was lowered from II (Orange; "probable eruption in term of days or weeks") to III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)


18 February-24 February 2009

INGEOMINAS reported an explosive eruption from Galeras that began at 0705 on 20 February; the Alert Level was raised from II (Orange; "probable eruption in term of days or weeks") to I (Red; "imminent eruption or in progress"), on a scale of 4-1. The eruption was accompanied by shock waves detected in several local communities and produced sounds heard in Popayán (about 160 km NNE). Observers from areas on the E flank reported two explosions, incandescent blocks ejected above the summit, ash emissions, and sulfur gas odor. An ash plume rose to an altitude of 12.5 km (41,000 ft) a.s.l. and drifted E, W, and N. Ashfall was reported in areas to the W. Gas plumes with a low ash content continued, especially in the afternoon, and rose 700 m above the summit. On 21 February, the Alert Level was lowered to back to II. During 22-24 February, occasional steam plumes rose 500 m above the summit and drifted NNW.

Source: Servicio Geológico Colombiano (SGC)


11 February-17 February 2009

INGEOMINAS reported an explosive eruption from Galeras that began at 1910 on 14 February; the Alert Level was raised from III (Yellow; "changes in the behavior of volcanic activity") to I (Red; "imminent eruption or in progress"), on a scale of 4-1. An accompanying shock wave was detected in multiple areas, including in parts of Pasto (about 10 km E). The altitude of the resultant ash plume was not known nor observed on satellite images due to cloud cover. From about 1930 until 2030 ashfall, rain, and an odor of sulfur gas were reported on the slopes of the volcano as well as in Pasto. Ash deposits were mainly in areas to the E and as far away as 25 km. Seismicity returned at 1950 to similar levels recorded prior to the eruption and remained low. On 16 February, the Alert Level was lowered to II (Orange; "probable eruption in term of days or weeks"). During 16-17 February, small steam plumes rose to altitudes of 4.6-6.7 km (15,100-22,000 ft) a.s.l. and drifted SE, E, and NE.

According to news articles, authorities ordered the evacuation of about 8,000 people living on the slopes, but few went to evacuation shelters.

Sources: Servicio Geológico Colombiano (SGC), Agence France-Presse (AFP), Caracol Radio


21 January-27 January 2009

INGEOMINAS reported that during 21, 23-24, and 26-27 January some grayish plumes from Galeras rose to altitudes of 5-6 km (16,400-19,700 ft) a.s.l. and drifted S and SW.

Source: Servicio Geológico Colombiano (SGC)


14 January-20 January 2009

INGEOMINAS reported that during 14-15 and 17-19 January some grayish plumes from Galeras rose to altitudes below 5.7 km (18,700 ft) a.s.l. and drifted S and SW.

Source: Servicio Geológico Colombiano (SGC)


10 December-16 December 2008

INGEOMINAS reported that thermal images of the lava dome in Galeras's crater were taken during an overflight on 11 December. The images revealed temperatures as hot as 530 degrees Celsius on the N side of the dome and temperatures near 80 degrees Celsius on the W side. Temperatures had declined compared to thermal images taken in October 2008. On 16 December, INGEOMINAS reported that during the previous few days, gas plumes rose to altitudes of 5.9-6.7 km (19,400-22,000 ft) a.s.l. and drifted NW.

Source: Servicio Geológico Colombiano (SGC)


26 November-2 December 2008

INGEOMINAS reported that on 30 November ash emissions from Galeras were associated with seismic tremor that lasted about 30 minutes. Resultant ash plumes drifted 6-12.5 km S and SSW.

Source: Servicio Geológico Colombiano (SGC)


5 November-11 November 2008

On 11 November, INGEOMINAS reported that during the previous week pulsating white plumes, occasionally tinged gray, rose from Galeras to altitudes of 4.5-5.7 km (14,800-18,700 ft) a.s.l. and drifted W.

Source: Servicio Geológico Colombiano (SGC)


29 October-4 November 2008

On 4 November, INGEOMINAS reported that during the previous week pulsating white plumes, occasionally tinged gray or blue, rose from Galeras to altitudes of 4.5-6.8 km (14,800-22,300 ft) a.s.l. and drifted W. During an overflight on 30 October, incandescence was observed on some parts of the lava dome.

Source: Servicio Geológico Colombiano (SGC)


22 October-28 October 2008

On 28 October, INGEOMINAS reported that during the previous week pulsating white plumes occasionally tinged gray rose from Galeras to altitudes of 4.7-5.5 km (15,400-18,000 ft) a.s.l. and drifted NW.

Source: Servicio Geológico Colombiano (SGC)


15 October-21 October 2008

On 21 October, INGEOMINAS reported that during the previous week pulsating white plumes occasionally tinged gray rose from Galeras to altitudes of 4.6-7.4 km (15,100-24,300 ft) a.s.l. and drifted S. On 20 October, a M 2.3 earthquake located 600 m SSW of the main crater occurred at a depth of less than 1 km.

Source: Servicio Geológico Colombiano (SGC)


17 September-23 September 2008

INGEOMINAS reported that incandescence was observed in Galeras's crater during an overflight on 19 September. Thermal images revealed a significant anomaly from the cone in the main crater that measured 550 degrees Celsius; other anomalies on the sides of the cone measured 270 degrees Celsius. Sulfur dioxide values were near 8,200 tonnes. Further measurements during 19-23 September revealed temperatures between 500 and 600 degrees Celsius and sulfur dioxide values between 3,000 and 5,200 tonnes.

Source: Servicio Geológico Colombiano (SGC)


10 September-16 September 2008

INGEOMINAS reported that a M 2 earthquake located S of Galeras occurred on 9 September at a depth of less than 1 km. The sulfur dioxide emission measurement was 14,500 tonnes the next day. During 11-16 September, the sulfur dioxide emission rate fluctuated between 3,200 and 6,800 tons. Gas plumes drifted W and NW.

Source: Servicio Geológico Colombiano (SGC)


23 January-29 January 2008

INGEOMINAS reported that white plumes from Galeras's main crater and gas emissions from several points along the margins of the crater were observed during aerial observations on 23 January. Plumes drifted W. Several impact craters were spotted; the largest one was about 15 m in diameter and 5 m deep. Thermal images of the main crater revealed a maximum temperature of 150 degrees Celsius.

Source: Servicio Geológico Colombiano (SGC)


16 January-22 January 2008

INGEOMINAS issued a report at 1000 on 17 January, noting that the seismic pattern from Galeras observed during the previous 24 hours was similar to patterns noted before past eruptions. Later that day, at 2006, an explosive eruption was registered by the seismic network and prompted INGEOMINAS to raise the Alert Level from 3 ("changes in the behavior of volcanic activity have been noted") to 1 ("imminent eruption or in course"), on a scale of 4-1.

Based on observations of satellite imagery and information from INGEOMINAS, the Washington VAAC reported that an ash plume rose to an altitude of 11 km (36,000 ft) a.s.l. at 2216 and drifted W on 17 January.

On 19 January, INGEOMINAS lowered the Alert Level to 2 ("likely eruption in days or weeks") because seismic events decreased in occurrence and energy. On 21 January, INGEOMINAS further lowered the Alert Level to 3 and reported that the initial ash plume from the eruption drifted SW, then W. Fine Ashfall was collected in Túquerres (about 32 km to the SW) and very fine ash was observed in neighborhoods of Ricaurte (about 71 km to the W). About 2 km away, military personnel reported that blocks 1.5 m in diameter were noted on a highway.

According to a news article, small settlements to the N were ordered to evacuate; about 100 people moved to shelters.

Sources: Servicio Geológico Colombiano (SGC), Washington Volcanic Ash Advisory Center (VAAC), Associated Press


9 January-15 January 2008

INGEOMINAS reported that steam-and-gas plumes from Galeras rose to an altitude of 6.3 km (20,700 ft) a.s.l. on 12 January. The emissions occasionally contained ash and were associated with episodes of spasmodic volcanic tremor.

Source: Servicio Geológico Colombiano (SGC)


26 December-1 January 2008

INGEOMINAS reported that an ash-and-gas plume from Galeras rose to an altitude of 4.9 km (16,100 ft) a.s.l. and drifted NW on 31 December. The emission was associated with an episode of spasmodic tremor. Another plume rose to an altitude of 4.5 km (14,800 ft) a.s.l. and drifted S.

Source: Servicio Geológico Colombiano (SGC)


28 November-4 December 2007

Based on visual observations during clear weather, INGEOMINAS reported that steam-and-gas plumes from Galeras rose to a maximum altitude of 5.3 km (17,400 ft) a.s.l. during 21-23 November and 3 December. The plumes occasionally contained small volumes of ash and were associated with seismic tremor. Gas and ash plumes that rose to an altitude of 4.4 km (14,400 ft) a.s.l. and drifted NW were observed during an overflight on 27 November. Thermal images indicated an increase in temperatures since a 2 October overflight at the point sources of emissions. The Alert Level remained at 3 (changes in the behavior of volcanic activity have been noted) on a scale of 4-1.

Source: Servicio Geológico Colombiano (SGC)


31 October-6 November 2007

Based on visual observations during clear weather, INGEOMINAS reported that steam-and-ash plumes from Galeras rose to a maximum altitude of 5.7 km (18,700 ft) a.s.l. during 29 October-4 November. The Alert Level remained at 3 (changes in the behavior of volcanic activity have been noted) on a scale of 4-1.

Source: Servicio Geológico Colombiano (SGC)


3 October-9 October 2007

INGEOMINAS reported that during 4-5 October, steam plumes from Galeras rose to altitudes of 5.8-6.3 km (19,000-20,700 ft) a.s.l. Occasional pulses of ash accompanied the steam emissions. Plumes drifted N and NW. The Alert Level remained at 3 (changes in the behavior of volcanic activity have been noted) on a scale of 4-1.

Source: Servicio Geológico Colombiano (SGC)


21 March-27 March 2007

On 20 March, INGEOMINAS reported that the Alert Level for Galeras was decreased from 2 (probable eruption in days to weeks) to 3 (changes in the behavior of volcanic activity have been noted) on a scale of 4-1 due to decreased seismicity, low gas emissions, and no indication of changes below the surface of the lava dome.

Source: Servicio Geológico Colombiano (SGC)


6 December-12 December 2006

On 22 November INGEOMINAS reported that the Alert Level for Galeras was increased from 3 (changes in the behavior of volcanic activity have been noted) to 2 (probable eruption in days to weeks) on a scale of 4-1, due to seismic patterns previously indicative of eruptive episodes. Emissions of gas and steam were seen coming from the periphery of the main crater during aerial observations on 4, 5, 10, and 11 December.

Source: Servicio Geológico Colombiano (SGC)


19 July-25 July 2006

On 17 July, INGEOMINAS (Instituto Colombiano de Geología y Minería) reported that after the 12 July eruption of Galeras, seismic activity decreased considerably. Observations of the dome and secondary craters in the W sector post-12 July, showed small physical changes. Gas plumes with little steam content were observed without associated seismic activity. Galeras remained at Alert Level 3 (changes in the behavior of volcanic activity have been noted).

Source: Servicio Geológico Colombiano (SGC)


12 July-18 July 2006

According to a news article, on 12 July the Colombian government ordered the evacuation of ~10,000 people living near Galeras due to an increase in volcanic activity. INGEOMINAS reported an increase in seismic activity and at least two explosive eruptions. Ash accumulated about 10 km N and NE in the towns of La Florida and Nariño and 5 km NE in the town of Genoy. The Alert Level was increased from 2 (probable eruption in days to weeks) to 1 (eruption imminent or occurring). On 13 July, due to a decrease in activity, the Alert Level was lowered from 1 to 3 (changes in the behavior of volcanic activity have been noted). Approximately 2,000 people had been taken to shelters.

Sources: Servicio Geológico Colombiano (SGC), Reuters, Associated Press, BBC News


14 June-20 June 2006

INGEOMINAS reported that during 12-19 June, the number of pulsating ash emissions at Galeras decreased from the 5-12 June reporting period. Ash columns reached heights of 1.4 km above the summit (18,600 ft a.s.l.) on 12 June and 0.6 km above the summit (16,000 ft a.s.l.) on 15 June. Galeras remained at Alert Level 2 (likely eruption in days or weeks).

Source: Servicio Geológico Colombiano (SGC)


17 May-23 May 2006

INGEOMINAS reported that during 15-22 May, a partially solidified lava dome remained in the main crater of Galeras. Seismicity and the sulfur-dioxide flux continued at very low levels. Galeras remained at Alert Level 2 (likely eruption in days or weeks).

Source: Servicio Geológico Colombiano (SGC)


10 May-16 May 2006

INGEOMINAS reported that during 9-15 May, a partially solidified lava dome remained in Galeras' main crater. Seismicity and the sulfur-dioxide flux continued at low levels. Gas and sporadic ash emissions rose to low levels. Galeras remained at Alert Level 2 (likely eruption in days or weeks).

Source: Servicio Geológico Colombiano (SGC)


3 May-9 May 2006

INGEOMINAS reported that Galeras remained at a critical state during 1-8 May, with a partially solidified lava dome in the main crater and low levels of seismicity. The sulfur-dioxide flux continued at very low levels. Galeras remained at Alert Level 2 (likely eruption in days or weeks).

Source: Servicio Geológico Colombiano (SGC)


26 April-2 May 2006

INGEOMINAS reported that Galeras remained at a critical state during 21 April to 1 May, with a partially solidified lava dome in the main crater and low levels of seismicity. The sulfur-dioxide flux continued at low levels. Galeras remained at Alert Level 2 (likely eruption in days or weeks).

Source: Servicio Geológico Colombiano (SGC)


19 April-25 April 2006

INGEOMINAS reported that Galeras remained at a critical state during 18-24 April, with a partially solidified lava dome in the main crater and low levels of seismicity. Galeras remained at Alert Level 2 (likely eruption in days or weeks).

Source: Servicio Geológico Colombiano (SGC)


12 April-18 April 2006

INGEOMINAS reported that Galeras remained at a critical state during 10-17 April, with a partially solidified lava dome in the main crater. Seismicity continued to decrease, with an average of 70 small earthquakes occurring at the beginning of the report week, and an average of 45 occurring at the end of the week. In addition, there were small gas emissions from the volcano. Galeras remained at Alert Level 2 (likely eruption in days or weeks).

Source: Servicio Geológico Colombiano (SGC)


5 April-11 April 2006

INGEOMINAS reported that Galeras remained at a critical state during 5-10 April, with a partially solidified lava dome in the main crater. Decreases were observed in various measured parameters at the volcano, including seismicity, deformation, gas emissions, and temperatures. According to INGEOMINAS, most of the explosive eruptions at Galeras in the past 17 years occurred when parameters were at similarly low levels. In addition, the current lava dome has a significantly greater volume than the dome that was destroyed during an eruption in 1992. Also, the volume of magma in the interior of the volcanic system is greater than during 1989-1993. Galeras remained at Alert Level 2 (likely eruption in days or weeks).

Source: Servicio Geológico Colombiano (SGC)


29 March-4 April 2006

An increase in the energy of earthquakes at Galeras, which began on 28 March, ended on the 29th. The number of earthquakes beneath the volcano decreased during 28 March to 3 April (an average of 66 earthquakes was recorded daily), in comparison to the previous week (an average of 89 earthquakes was recorded daily). During the report period, steam columns rose up to ~500 m above the volcano (or 15,700 ft a.s.l.) and the outer layer of the lava dome at the volcano's summit cooled in comparison to previous weeks. Galeras remained at Alert Level 2 ("likely eruption in days or weeks").

Source: Servicio Geológico Colombiano (SGC)


22 March-28 March 2006

Due to an increase in tremor at Galeras beginning on the morning of 28 March, INGEOMINAS raised the Alert Level from 3 ("changes in the behavior of volcanic activity have been noted") to 2 ("likely eruption in days or weeks"). On the 28th, energetic signals and tremor began that had been absent during previous weeks. In addition, seismic instruments detected very shallow low-energy hybrid signals, similar to ones recorded during 1991-1993 when dome emplacement occurred on the main crater's floor.

Sources: Servicio Geológico Colombiano (SGC), Reuters


15 March-21 March 2006

During 13-20 March, seismicity at Galeras decreased in comparison to previous weeks and deformation was measured at the volcano. Plumes of mainly steam, gas, and small amounts of ash were emitted from the volcano and rose to a maximum height of 1.2 km above the volcano (or 18,000 ft a.s.l.). Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").

Source: Servicio Geológico Colombiano (SGC)


1 March-7 March 2006

During 27 February to 6 March, there were variations in the rate of degassing at Galeras and an increase in the volume of the lava dome located in the main crater in comparison to the previous week. Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").

Source: Servicio Geológico Colombiano (SGC)


22 February-28 February 2006

During 20-27 February, seismicity continued at Galeras, with an average of 280 small earthquakes occurring per day. On 26 February seismic stations detected a cluster of earthquakes. A shallow M 4.8 volcano-tectonic earthquake was registered below the volcano at 1009, followed by 35 smaller earthquakes. Slight deformation was recorded at the volcano. A flux of about 600 metric tons of sulfur dioxide was measured per day. Steam and gas rose to ~700 m above the volcano (or 16,300 ft a.s.l.). Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").

Source: Servicio Geológico Colombiano (SGC)


15 February-21 February 2006

During 13-20 February, seismicity continued at Galeras, with an average of about 190 small earthquakes occurring per day. A flux of about 200 metric tons of sulfur dioxide was measured daily. Steam and gas rose to ~1.1 km above the volcano (or ~17,600 ft a.s.l.) on 19 February. Incandescence was visible at parts of the lava dome. The volume of the lava dome in the main crater was approximately 1.5 times larger than when it was first observed on 13 January. Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").

Note: It was incorrectly reported in the 8-14 February Weekly Volcanic Activity Report that on 8 February pyroclastic-flow deposits were found at Galeras. Pyroclastic-fall deposits were observed.

Source: Servicio Geológico Colombiano (SGC)


8 February-14 February 2006

INGEOMINAS reported on 10 February that a lava dome was growing inside the main crater of Galeras. The lava dome was not seen during the previous observation flight on 16 January. Seismicity was dominated by long-period earthquakes, with an average of 150 occurring daily during 13 January to 8 February. On 5 February, strong degassing was visible from different parts of the active cone and around the lava dome. Cracks were visible on the high parts of the lava dome. During a field visit on 8 February, scientists found fall material [originally incorrectly reported in the WVAR as pyroclastic-flow deposits] high on the SE flank of the volcano. The exact date of the small emission was not known, but it occurred after 26 November when scientists previously visited the area. Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").

Source: Servicio Geológico Colombiano (SGC)


1 February-7 February 2006

During 30 January to 6 February, seismicity continued at Galeras, with an average of 200 small earthquakes occurring per day. In addition, slight deformation was recorded at the volcano. A flux of about 300 metric tons of sulfur dioxide was measured per day. Strong degassing occurred in several sectors of the active cone and around the lava dome. Steam rose to ~900 m above the volcano (or ~17,000 ft a.s.l.). Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").

Source: Servicio Geológico Colombiano (SGC)


25 January-31 January 2006

During 23-30 January, a lava dome continued to grow in the main crater of Galeras, and strong degassing occurred in several areas of the active cone and around the dome. Seismicity continued that was associated with the movement of fluid within the volcano, and slight deformation was recorded. Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").

Source: Servicio Geológico Colombiano (SGC)


11 January-17 January 2006

During a flight over Galeras on 13 January, scientists saw a lava dome in the volcano's main crater. Around this time, there was an increase in the amount of seismicity and deformation. Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").

Source: Servicio Geológico Colombiano (SGC)


4 January-10 January 2006

During 2-9 January, Galeras emitted gas and small amounts of ash. In addition, heightened seismicity continued and small changes in deformation were measured. The sulfur-dioxide flux from the volcano varied between 490 and 1,500 metric tons per day. Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").

Source: Servicio Geológico Colombiano (SGC)


28 December-3 January 2006

During 23 December to 2 January, Galeras emitted gas and small amounts of ash. On the 23rd, four events produced ash plumes that rose to ~3 km above the volcano (or 23,900 ft a.s.l.) and drifted toward the sector of Consacá, ~13 km WSW. A cluster of 33 volcano-tectonic earthquakes occurred beneath the volcano's crater during 29-30 December. The earthquakes reached a maximum magnitude of 1.2. The sulfur-dioxide flux at the volcano varied between 300 and 1,500 tons per day. Galeras remained at Alert Level 3 ("changes in the behavior of volcanic activity have been noted").

Source: Servicio Geológico Colombiano (SGC)


21 December-27 December 2005

Based on information from the US Geological Survey, the Washington VAAC reported that a pilot observed an ash plume from Galeras on 23 December at a height of ~7.3 km (24,000 ft) a.s.l. drifting W.

Source: Washington Volcanic Ash Advisory Center (VAAC)


7 December-13 December 2005

Due to a decrease in volcanic activity at Galeras, on 28 November INGEOMINAS reduced the Alert Level at the volcano from 2 (probable eruption in days to weeks) to 3 (changes in the behavior of volcanic activity have been noted). Through 12 December, seismicity was recorded that was indicative of fluids moving within the volcano, small changes in deformation occurred, and emitted gas rose to a height of ~500 m above the volcano (or 15,700 ft a.s.l.).

Source: Servicio Geológico Colombiano (SGC)


30 November-6 December 2005

The hazard status at Galeras was at Level III as of 5 December. Low levels of seismicity and deformation were continuing. Although poor weather conditions obscured the volcano most of the time, steam and gas emissions were photographed on 2 December coming from several locations on the active cone, including the main crater. The plume rose 1 km above the summit on 3 December.

Source: Servicio Geológico Colombiano (SGC)


23 November-29 November 2005

On 24 November at 0246 seismicity was recorded at Galeras that was associated with the beginning of an eruption. Ash from the eruption fell in the towns of Fontibon, San Cayetano, Postobon, and in north Pasto (E of the volcano). INGEOMINAS raised the Alert Level from 2 (probable eruption in days to weeks) to 1 (eruption imminent or occurring). The Washington VAAC observed a small puff of ash NE of the volcano at a height around ~4.6 km (15,000 ft) a.s.l. Activity decreased by the next day, so the Alert Level was reduced to 2. Thousands of people had been evacuated from the vicinity of the volcano during the week prior to the eruption.

Sources: Servicio Geológico Colombiano (SGC), Associated Press, Reuters


16 November-22 November 2005

Heightened seismic activity continued at Galeras during 16-22 November. According to news articles, only ~1,000 of the ~9,000 residents who were ordered to evacuate had left as of 18 November.

Sources: Servicio Geológico Colombiano (SGC), Associated Press


9 November-15 November 2005

INGEOMINAS reported that during 9-14 November, a large number of tornillo earthquakes (long-period seismic events related to pressurized fluid flow at shallow depth) continued to occur below Galeras. In the previous 2 weeks, 25 tornillos were recorded. The earthquakes had characteristics similar to those that occurred before eruptions in 1992-1993. A small amount of deformation was recorded at Galeras during the report period. Activity in the previous month suggested that the volume of magma beneath the volcano was greater than that inferred to have been present during the 1992-1993 eruptions. Due to the increased activity at Galeras, the Alert level was raised from 3 (changes in the behavior of volcanic activity have been noted) to 2 (probable eruption in days or weeks).

According to new reports, on 14 November local authorities recommended the voluntary evacuation of as many as 9,000 people living in towns near the volcano, including in parts of Pasto (to the W), La Florida (to the N), and Nariño (to the N).

Sources: Servicio Geológico Colombiano (SGC), El Tiempo, IOL News


2 November-8 November 2005

During 31 October to 7 November, low-level seismicity occurred at Galeras, including several tornillo earthquakes (long-period seismic events related to pressurized fluid flow at shallow depth). In addition, small amounts of deformation were recorded at the volcano. Galeras remained at Alert Level 3 (changes in the behavior of volcanic activity have been noted).

Source: Servicio Geológico Colombiano (SGC)


24 August-30 August 2005

Volcano-tectonic earthquakes that began at Galeras around 19 August continued through 29 August. The earthquakes occurred at depths of 5-8 km and reached M 4.6. No surficial changes were observed at the volcano.

Source: Servicio Geológico Colombiano (SGC)


17 August-23 August 2005

During 19-21 August, 30 volcano-tectonic earthquakes were recorded at Galeras. The earthquakes occurred 3-4 km NW of the volcano's active cone, near the towns of Santa Bárbara, Nariño, and La Florida. About five earthquakes felt by nearby populations occurred at depths of 8-6 km, with the largest (M 4.7) occurring at a depth of 6 km on 21 August. No significant deformation was observed at the volcano during the report period, and gas emission continued from the main and secondary craters.

Source: Servicio Geológico Colombiano (SGC)


10 August-16 August 2005

During 8-15 August, seismicity remained at low levels at Galeras and small amounts of deformation were recorded. The Alert Level remained at 3 (changes noted in the behavior of volcanic activity).

Source: Servicio Geológico Colombiano (SGC)


6 July-12 July 2005

During 4-11 July, seismicity remained at low levels at Galeras. An M 2.5 volcano-tectonic earthquake on 4 July was felt in sections of some towns near the volcano. During the report period, small amounts of deformation were recorded and low rates of gas discharge were noted.

Source: Servicio Geológico Colombiano (SGC)


8 June-14 June 2005

At Galeras during 6-13 June, there were low levels of seismicity, small amounts of deformation, and moderate gas emissions from the main crater. The alert remained at level 3 (changes in the behavior of volcanic activity have been noted).

Source: Servicio Geológico Colombiano (SGC)


18 May-24 May 2005

According to a news article, on 24 May the Colombian government ordered the evacuation of ~9,000 people living near Galeras due to an increase in volcanic activity. INGEOMINAS reported that during 16-23 May, small shallow earthquakes occurred beneath the volcano. There was an increase in earthquakes associated with fracturing within the volcano during the night of 21 May to the morning of 22 May. Gas emissions slightly decreased on 17 and 20 May in comparison to 29 April and 2 May, and slightly increased around 23 May. Deformation continued to be recorded at the volcano's summit. There were no ash emissions. Galeras remained at Alert Level 2 (probable eruption in terms of days or weeks) as it has since 19 April 2005.

Sources: Servicio Geológico Colombiano (SGC), Reuters


2 February-8 February 2005

During 31 January to 7 February, small gas-and-ash emissions continued at Galeras. Ash was deposited in the sectors of Consacá (~15 km W of the volcano) and La Florida (~10 km NW), and in the city of Pasto (~ 10 km E). Low-level seismicity and a small amount of deformation were recorded.

Sources: Servicio Geológico Colombiano (SGC), Washington Volcanic Ash Advisory Center (VAAC)


26 January-1 February 2005

During 25-31 January, low-level relatively shallow seismicity continued at Galeras, and a small amount of deformation towards the W portion of the volcanic cone occurred. On 30 January an emission of gas and ash rose ~800 m above the volcano.

Sources: Servicio Geológico Colombiano (SGC), Washington Volcanic Ash Advisory Center (VAAC)


6 January-12 January 2005

During 30 May to 6 June, there was a decrease in seismicity and deformation at Galeras in comparison to the previous week. The number and magnitude of earthquakes decreased and there were smaller changes in deformation. The level of alert was decreased from 2 (probable eruption in days or weeks) to 3 (changes in the behavior of volcanic activity have been noted).

Source: Servicio Geológico Colombiano (SGC)


17 November-23 November 2004

Galeras volcano erupted explosively on 21 November at 1544, Instituto Colombiano de Geología y Minería reported. The eruption produced a shock wave felt as far away as Cimarrones (18 km N of the volcano), Chachagui (17 km N of the volcano), and Laguna de La Cocha (20 km SW of the volcano). Effects of the shock wave varied from a loud roar, to the vibration of large windows, to the feeling of an earthquake. Ballistic rock blocks were expelled and fell nearly 3 km from the volcano on its eastern flank, producing short-lived forest fires. The eruption produced an ash-and-gas column that rose to an estimated height of 9-10 km a.s.l and drifted to the S and W. The Washington VAAC reported that satellite imagery through 2015 on 21 November revealed that high level ash estimated to be near 9 km a.s.l had moved to the W, while low level ash estimated to be near 4-5 km a.s.l remained in the vicinity of the summit of the volcano and showed little motion.

Sources: Servicio Geológico Colombiano (SGC), Washington Volcanic Ash Advisory Center (VAAC)


6 October-12 October 2004

During 8-11 October, emissions of gas and fine ash continued at Galeras. Plumes rose to a maximum height of ~1.5 km above the volcano. Small-amplitude tremor associated with gas-and-ash emissions was recorded.

Source: Servicio Geológico Colombiano (SGC)


22 September-28 September 2004

During 23-27 September, tremor associated with ash-and-gas emissions was recorded at Galeras. On the 23rd, ash deposits were seen on the upper portions of the volcano's N flank. By the 27th the amount of tremor had decreased significantly, which may have coincided with a decrease in ash emissions.

Source: Servicio Geológico Colombiano (SGC)


25 August-31 August 2004

INGEOMINAS reported that at Galeras during 19 August to 1 September, there was a decrease in the level of seismicity and the number of ash emissions. Gas-and-steam emissions continued.

Source: Servicio Geológico Colombiano (SGC)


18 August-24 August 2004

INGEOMINAS reported that gas-and-ash emissions continued at Galeras as of 18 August. Ash fell in villages near the volcano, including La Florida, Sandoná, El Ingenio (within 15 km of the volcano), and farther afield in Samaniego and Sotomayor (between 20 and 40 km from the volcano).

Sources: Servicio Geológico Colombiano (SGC), Washington Volcanic Ash Advisory Center (VAAC)


11 August-17 August 2004

INGEOMINAS reported that volcanic and seismic activity increased at Galeras on 11 August at 2349 when an eruption began that sentan ash-and-gas cloud to an unknown height and generated visible incandescence. According to the Washington VAAC, satellite imagery showed that an ash plume rose to a height of ~10.7 km a.s.l. It spread in all directions, but mainly to the NE, E, and SW. Later in the day, a thin plume at a height of ~7.3 km a.s.l drifted SW into northern Ecuador. A plume also drifted NW at a height of ~6.1 km a.s.l. By 1315 ash was no longer visible on satellite imagery. Fine ash was deposited in villages near the volcano including, La Florida (~10 km NW of the volcano), Nariño, Sandoná, and Consacá, and farther afield in Ancuya, Linares, and Sotomayor (~ 40 km NW of the volcano).

News articles reported that ~230 families were evacuated mainly from the volcano's N flank. Ash contaminated potable water in some villages, impacted farm animal's health, and left hundreds of dead fish floating in rivers. The village of La Florida was most strongly impacted by the eruption. On 16 August, ash emissions continued, depositing ash in several villages. A thin plume was visible on satellite imagery extending ~75 km NW.

Sources: Servicio Geológico Colombiano (SGC), Washington Volcanic Ash Advisory Center (VAAC), El Spectador, El Pais


4 August-10 August 2004

According to the Washington VAAC, several ash plumes emitted from Galeras were visible on satellite imagery during 7-10 August. The highest rising plume reached about 6 km a.s.l.

Source: Washington Volcanic Ash Advisory Center (VAAC)


28 July-3 August 2004

Satellite imagery showed a faint ash plume emitted from Galeras on 29 July around 0745. The height and direction of the plume was unknown.

Source: Washington Volcanic Ash Advisory Center (VAAC)


21 July-27 July 2004

Based on information from IG, the Washington VAAC reported that an activity increase at Galeras during several days prior to 24 July consisted of emissions that rose ~600 m above the volcano's summit. Ash was not visible on satellite imagery. According to a news report, a wide area around the volcano was declared off limits to visitors.

Sources: Washington Volcanic Ash Advisory Center (VAAC), Associated Press


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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2012 May 13 2013 May 21 (in or after) Confirmed 2 Historical Observations Summit crater
[ 2011 Mar 31 ] [ 2011 Apr 1 ] Uncertain     Summit crater
2010 Aug 25 2010 Aug 25 Confirmed 2 Historical Observations
2008 Oct 21 (?) 2010 Jan 2 (?) Confirmed 3 Historical Observations
2007 Oct 4 2008 Jan 17 Confirmed 3 Historical Observations
2005 Nov 24 2006 Jul 12 Confirmed 2 Historical Observations
2004 Jul 16 2005 Feb 7 (?) Confirmed 3 Historical Observations El Pinta vent
2002 Jun 7 2002 Jun 7 (?) Confirmed 1 Historical Observations El Pinta vent
2000 Mar 21 2000 May 18 Confirmed 1 Historical Observations
1993 Jan 14 1993 Jun 7 Confirmed 2 Historical Observations Summit crater, west, SW, & south rims
1990 Jan 7 1992 Jul 16 Confirmed 2 Historical Observations
1989 Feb 19 1989 May 9 Confirmed 2 Historical Observations El Pinta vent
1974 1983 (continuing) Confirmed 1 Historical Observations
[ 1973 May ] [ Unknown ] Uncertain 2  
1950 Jan 12 1950 Sep 5 Confirmed 2 Historical Observations
[ 1947 Jul 15 ] [ Unknown ] Uncertain 2  
1936 Feb 9 1936 Aug 27 (?) Confirmed 2 Historical Observations
[ 1933 ] [ Unknown ] Uncertain    
1932 Oct 10 Unknown Confirmed 2 Historical Observations
[ 1930 Apr 17 ] [ Unknown ] Uncertain    
1924 Oct 1927 Confirmed 3 Historical Observations
1923 Dec 8 Unknown Confirmed 2 Historical Observations
1891 Unknown Confirmed 2 Historical Observations
1889 Jul 3 Unknown Confirmed 2 Historical Observations
1865 Oct 2 1870 Confirmed 3 Historical Observations
[ 1836 ] [ Unknown ] Uncertain 2  
1834 Unknown Confirmed 2 Historical Observations
1828 Oct 24 1834 Mar Confirmed 3 Historical Observations
1823 Jun 17 1823 Jun 24 Confirmed 2 Historical Observations
1796 Nov 1801 Confirmed 2 Historical Observations
1754 1756 Confirmed 2 Historical Observations
1670 1736 Confirmed 3 Historical Observations
1641 1643 Confirmed 3 Historical Observations
1616 Jul 4 1616 Jul 4 Confirmed 3 Historical Observations
1580 Dec 7 1580 Dec 7 Confirmed 3 Historical Observations
1535 Unknown Confirmed 3 Historical Observations
0890 ± 200 years Unknown Confirmed 2 Radiocarbon (corrected)
0490 BCE ± 100 years Unknown Confirmed 2 Radiocarbon (corrected)
1160 BCE ± 300 years Unknown Confirmed 2 Radiocarbon (corrected)
2580 BCE ± 500 years Unknown Confirmed 2 Radiocarbon (corrected)
3150 BCE ± 200 years Unknown Confirmed 3 Radiocarbon (corrected)
7050 BCE ± 1000 years Unknown Confirmed   Tephrochronology

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.

Banks N G, Calvache-V M L, Williams S N, 1997. 14C ages and activity for the past 50 ka at Volcan Galeras, Colombia. J Volc Geotherm Res, 77: 39-55.

Calvache-V M L, 1990. Geology and volcanology of the recent evolution of Galeras volcano, Colombia. Unpublished MSci thesis, Louisiana State Univ, 172 p.

Calvache-V M L, Cortes-J G P, Williams S N, 1997. Stratigraphy and chronology of the Galeras volcanic complex, Colombia. J Volc Geotherm Res, 77: 5-19.

Calvache-V M L, Williams S N, 1997. Geochemistry and petrology of the Galeras volcanic complex, Colombia. J Volc Geotherm Res, 77: 21-38.

Cepeda H, Munoz F, Acevedo A P, Gil F, Pulgarin B, Nieto A, Londono A, Mejia I, Calvache M L, Mora H, Carvajal C A, Banks N, 1989. Reactivacion del Volcan Galeras, Colombia, Suramerica. Unpublished manuscript, 6 p.

Cortes-J G P, Raigosa-A J, 1997. A synthesis of the recent activity of Galeras volcano, Colombia: seven years of continuous surveillance, 1989-1995. J Volc Geotherm Res, 77: 101-114.

Cuellar-Rodriguez J V, Ramirez-Lopez C, 1987. Descripcion de los volcanes Colombianos. Rev CIAF, Bogota, p 189-222.

Hantke G, Parodi I, 1966. Colombia, Ecuador and Peru. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 19: 1-73.

Hurtado-Artunduaga A D, Cortez-Jimenez G P, 1997. Third version of the hazard map of Galeras volcano, Colombia. J Volc Geotherm Res, 77: 89-100.

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

Mendez Fajury R A, 1989. Catalogo de los volcanes activos en Colombia. Bol Geol INGEOMINAS, Colombia, 30: 1-75.

Ordonez M I, Cepeda H, 1997. Morphological changes of the active cone of Galeras volcano, Colombia, during the last century. J Volc Geotherm Res, 77: 71-87.

Galeras, a stratovolcano with a large breached caldera located immediately west of the city of Pasto, is one of Colombia's most frequently active volcanoes. The dominantly andesitic Galeras volcanic complex has been active for more than 1 million years, and two major caldera collapse eruptions took place during the late Pleistocene. Long-term extensive hydrothermal alteration has affected the volcano. This has contributed to large-scale edifice collapse that has occurred on at least three occasions, producing debris avalanches that swept to the west and left a large horseshoe-shaped caldera inside which the modern cone has been constructed. Major explosive eruptions since the mid Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks. A central cone slightly lower than the caldera rim has been the site of numerous small-to-moderate historical eruptions since the time of the Spanish conquistadors.