Galeras Volcano | John Seach



1.22 N, 77.37 W
summit elevation 4276 m
complex volcano

Galeras volcano is located in southern Colombia close to the border with Ecuador. The volcanic complex consists of several small calderas, cinder cones and a stratovolcano. Two caldera forming events have occurred at the volcano. 560,000 years ago, and sometime between 40,000 and 150,000 years ago.

The city of Pasto with 450,000 inhabitants is located on the eastern slope of Galeras. The regional Romeral-Buesaco fault system intersects the volcano along NE-SW axes, and the Pasto fault traverses the edifice on its southeastern flank.

2012-14 Eruptions
Ash emissions occurred at the volcano between 2012-14.

2010 Eruption
An eruption occurred at Galeras volcano on 2nd January 2010. ash was ejected to a height of 12 km. Hot lava fell 3.5 km from the volcano and started fires.

2009 Eruptions
Ash plumes were visible at Galeras volcano between 14-27 January 2009. Ash reached a maximum height of 6 km above sea level. Up to 8000 people were evacuated from around the volcano after an explosive eruption of Galeras on 14th February 2009. Ash fell in the city of Pasto.

An eruption occurred at Galeras volcano, Colombia on 20th February 2009 at 7:05 am, local time. The eruption was accompanied by shock waves, and and vibrations in several villages located in the catchment area of the volcano. There are confirmed reports that the eruption was heard in the city of Popayan, over 150 km NNE of the volcano. There were at least two explosions, and emission of incandescent material, along with a sulphurous smell. The initial eruptive event was associated with a seismic signal which lasted for approximately 13 minutes. The seismic energy was almost twice the assessed for the eruption of 14th February 2009. Wind direction according to the weather station installed at the top of Galeras, is toward the west coast. There are reports of ash fall in areas of the municipalities of Sandona, Consacá and Ancuya, located on the western flank of Galeras. The eruptive column showed three levels of dispersion. The column reached a height of about 8 km, with dispersal to the east, at an altitude of 2500 m, the plume of ash was to the west, and between these two levels, the ash moved north. This dispersion was due to variable wind conditions at different altitudes. After the eruption there was a decrease in seismic activity, characterized by the presence of a few events associated with fluid dynamics and low energy levels.

Galeras Volcano, Colombia An explosive eruption occurred at Galeras volcano, Colombia at 9:14 am on 30th September 2009. The eruption was accompanied by acoustic waves. National Parks staff at the western rim of the volcano reported two explosions with the ejection of incandescent material at the active cone. An ash column reached a height of 8-11 km above the summit. Sulphur dioxide measurements made between 9:30 and 10:00 am showed high levels between 1100 and 9300 tons/day. Ashfall was reported in the Municipalities of Sandona, Ancuya, Linares, La Llanada, and Sotomayor. The eruptive event was similar in size to that of 20th February 2009. After the eruption seismicity decreased. Due to the presence of magma close to the surface, and the history of the volcano, INGEOMINAS has raised the alert status to the highest level RED.

An eruption occurred at Galeras volcano, Colombia on 20th November 2009, causing 1000 evacuations. The eruption occurred at 8:37 am and was accompanied by sound which was heard by residents surrounding the volcano. The eruption column was estimated at 10 km high and drifting north. The seismic signal associated with the eruption was lower than that recorded during the eruption of 30th September 2009. The locals were taken to shelters in Pasto, the capital of Narino department on the border with Ecuador. Traffic restrictions have affected the highway linking Pashto to areas close to Galeras. The eruption caused ashfall in Pashto and surrounding villages.

2008 Eruption
An explosive eruption occurred at Galeras on 17th January 2008. Seismicity of the event was similar to that preceding eruptions in 1992, 1993, and 2004-2006. Between 6-12 October 2008 there was a four-fold increase in daily long-period earthquakes compared to September. A lava dome continued to grow in the crater.

2006 Eruptions
Between January and June 2006 a lava dome continued to grow in the crater at Galeras volcano. On the 12th July there was an increase in activity which includes two explosions and 1000 people were evacuated from the surrounding areas.

2005 Eruptions
Between 16-23 May 2005, small shallow earthquakes were recorded beneath Galeras volcano. On 24th May 9000 people were evacuated from near the volcano as a precaution. Galeras erupted on 24th November after tornillo earthquakes were registered at the volcano. Ash fell at Fontibon, San Cayetano, Postobon, and north Pasto.

2004 Eruption
Galeras ash emissions occurred at El Pinta crater on 16th July. Elevated levels of gas emission were recorded at El Pinta crater and Deformes fumarole field from 17-20 July. On 21st July, an ash emission rose 500 m above the volcano's rim, and was visible from San Juan de Pasto. Ash from 11th August eruption fell on La Florida (10 km NW), Nariño, Sandoná, and Consacá. Maximum ashfall distance was at Ancuya, Linares, and Sotomayor (40 km NW). On 21st November 2004 there was an explosive eruption at Galeras. An eruption shock wave was felt as far away as Cimarrones (18 km N), Chachagui (17 km N), and Laguna de La Cocha (20 km SW). Projectiles fell 3 km from the crater starting fires.

2002 Eruption
A hydrothermal eruption occurred on 7th June 2002 at El Pinta Crater. The eruption ejected lapilli, ash, and clay.

2000 Eruptions
Two small eruption occurred in 2000 after seven years of quiet at Galeras volcano. The first eruption was on 21st March, and the second eruption on 5th April, The eruptions were preceded by tornillo earthquakes.

1993 Eruption and Fatalities
Six volcanologists and three tourists were killed in the crater of Galeras on 14th January 1993. Twenty people were in the crater when the volcano erupted. Twenty tornillo earthquakes occurred at the volcano in 16 days prior to the eruption. The previous eruption at Galeras on 16th July 1992 was preceded by 9 tornillo earthquakes in 5 days. Despite the pre-eruption earthquakes, the scientists still entered the crater. Some of the people who entered the crater did not wear a helmet or take other safety gear.

1989 Eruptions
In May 1989, a series of semi-continuous vulcanian eruptions were recorded at Galeras volcano.

Further reading
Narváez, L., Cepeda, H. and Stix, J., 1997. ‘Tornillo’-type seismic signals at Galeras volcano, Colombia, 1992–1993. Journal of volcanology and geothermal research77(1-4), pp.159-171.

Baxter, Peter J., and Austin Gresham. "Deaths and injuries in the eruption of Galeras Volcano, Colombia, 14 January 1993." Journal of Volcanology and Geothermal Research 77.1-4 (1997): 325-338.

Stix, John, et al. "A model of vulcanian eruptions at Galeras volcano, Colombia." Journal of Volcanology and Geothermal Research 77.1-4 (1997): 285-303.

Galeras Volcano Eruptions

2012-14, 2008-10, 2004-06, 2002, 2000, 1993, 1990-92, 1989, 1974-83, 1973?, 1950, 1947?, 1936, 1933?, 1932, 1930?, 1924-27, 1923, 1891, 1889, 1865-70, 1836, 1828-34, 1823, 1796-1801, 1754-56, 1670-1736, 1616, 1580, 1535

Most eruptions from Galeras are short and violent.