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Colombia Volcanoes

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    Nevado del Ruiz

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    Nevado del Ruiz

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    Galeras

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    Chiles-Cerro Negro

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    Nevado del Ruiz

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    Purace

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    Nevado del Tolima

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    Cerro Bravo

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    Chiles-Cerro Negro

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    Nevado del Ruiz

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    Nevado del Huila

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    Sotara

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    Nevado del Ruiz

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    Machin

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    Nevado del Ruiz

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    Santa Isabel

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    Nevado del Tolima

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    Nevado del Ruiz

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    Nevado del Ruiz

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    Nevado del Ruiz

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Colombia has 14 Holocene volcanoes. Note that as a scientific organization we provide these listings for informational purposes only, with no international legal or policy implications. Volcanoes will be included on this list if they are within the boundaries of a country, on a shared boundary or area, in a remote territory, or within a maritime Exclusive Economic Zone. Bolded volcanoes have erupted within the past 20 years. Suggestions and data updates are always welcome ().

Volcano Name Location Last Eruption Primary Volcano Type
Azufral Colombia 930 BCE Stratovolcano
Cerro Bravo Colombia 1720 CE Stratovolcano
Chiles-Cerro Negro Colombia-Ecuador 1936 CE Stratovolcano
Cumbal Colombia 1926 CE Stratovolcano
Dona Juana Colombia 1906 CE Stratovolcano
Galeras Colombia 2014 CE Complex
Nevado del Huila Colombia 2012 CE Stratovolcano
Machin Colombia 1180 CE Stratovolcano
Purace Colombia 2022 CE Stratovolcano(es)
Romeral Colombia 5390 BCE Stratovolcano
Nevado del Ruiz Colombia 2022 CE Stratovolcano
Santa Isabel Colombia 850 BCE Shield
Sotara Colombia Unknown - Evidence Credible Stratovolcano
Nevado del Tolima Colombia 1943 CE Stratovolcano

Chronological listing of known Holocene eruptions (confirmed or uncertain) from volcanoes in Colombia. Bolded eruptions indicate continuing activity.

Volcano Name Start Date Stop Date Certainty VEI Evidence
Purace 2022 Mar 29 2022 Mar 29 Confirmed   Observations: Reported
Ruiz, Nevado del 2014 Nov 18 2022 Aug 12 (continuing) Confirmed 2 Observations: Reported
Galeras 2012 May 13 2014 Jan 30 ± 1 days Confirmed 2 Observations: Reported
Ruiz, Nevado del 2012 Feb 22 2013 Jul 12 (?) Confirmed 3 Observations: Reported
Galeras [2011 Mar 31] [2011 Apr 1] Uncertain  
Galeras 2010 Aug 25 2010 Aug 25 Confirmed 2 Observations: Reported
Huila, Nevado del 2008 Oct 26 (?) 2012 Jan 14 (?) Confirmed 3 Observations: Reported
Galeras 2008 Oct 21 (?) 2010 Jan 2 (?) Confirmed 3 Observations: Reported
Huila, Nevado del 2008 Jan 2 2008 Apr 16 (?) ± 15 days Confirmed 2 Observations: Reported
Galeras 2007 Oct 4 2008 Jan 17 Confirmed 3 Observations: Reported
Huila, Nevado del 2007 Feb 19 2007 May 28 (?) Confirmed 3 Observations: Reported
Galeras 2005 Nov 24 2006 Jul 12 Confirmed 2 Observations: Reported
Galeras 2004 Jul 16 2005 Feb 7 (?) Confirmed 3 Observations: Reported
Galeras 2002 Jun 7 2002 Jun 7 (?) Confirmed 1 Observations: Reported
Galeras 2000 Mar 21 2000 May 18 Confirmed 1 Observations: Reported
Ruiz, Nevado del [1994 Apr 23] [1994 Apr 23] Uncertain  
Galeras 1993 Jan 14 1993 Jun 7 Confirmed 2 Observations: Reported
Galeras 1990 Jan 7 1992 Jul 16 Confirmed 2 Observations: Reported
Galeras 1989 Feb 19 1989 May 9 Confirmed 2 Observations: Reported
Ruiz, Nevado del 1985 Sep 11 1991 Jul 13 Confirmed 3 Observations: Reported
Ruiz, Nevado del 1984 Dec 22 1985 Mar 19 (?) Confirmed 1 Observations: Reported
Purace 1977 Mar 19 1977 Mar 28 (?) Confirmed 2 Observations: Reported
Galeras 1974 Jul 2 ± 182 days 1983 Jul 2 (?) ± 182 days Confirmed 1 Observations: Reported
Galeras [1973 May 16 ± 15 days] [Unknown] Uncertain  
Purace 1957 Jul 2 ± 182 days Unknown Confirmed 2 Observations: Reported
Purace 1956 Jul 2 (in or before) ± 182 days Unknown Confirmed 2 Observations: Reported
Galeras 1950 Jan 12 1950 Sep 5 Confirmed 2 Observations: Reported
Purace 1949 May 26 1949 Jun 11 Confirmed 2 Observations: Reported
Galeras [1947 Jul 15] [Unknown] Uncertain  
Purace 1947 Apr 27 Unknown Confirmed 2 Observations: Reported
Purace 1946 Mar 1946 Apr Confirmed 2 Observations: Reported
Tolima, Nevado del 1943 Mar Unknown Confirmed 2 Observations: Reported
Chiles-Cerro Negro 1936 Jul 17 Unknown Confirmed 2 Observations: Reported
Galeras 1936 Feb 9 1936 Aug 27 (?) Confirmed 2 Observations: Reported
Galeras [1933] [Unknown] Uncertain  
Galeras 1932 Oct 10 Unknown Confirmed 2 Observations: Reported
Galeras [1930 Apr 17] [Unknown] Uncertain  
Purace 1927 Unknown Confirmed 2 Observations: Reported
Cumbal 1926 Dec 20 1926 Dec 21 Confirmed 2 Observations: Reported
Purace 1926 Aug 1926 Sep Confirmed 2 Observations: Reported
Purace 1925 Oct 12 1925 Nov 5 Confirmed 2 Observations: Reported
Galeras 1924 Oct 1927 Confirmed 3 Observations: Reported
Purace 1924 Unknown Confirmed 2 Observations: Reported
Galeras 1923 Dec 8 Unknown Confirmed 2 Observations: Reported
Ruiz, Nevado del 1916 Unknown Confirmed 2 Observations: Reported
Purace 1906 Unknown Confirmed 2 Observations: Reported
Purace 1902 (?) Unknown Confirmed 2 Observations: Reported
Purace 1899 Unknown Confirmed 2 Observations: Reported
Dona Juana 1897 Nov 1 1906 Confirmed 4 Observations: Reported
Galeras 1891 Unknown Confirmed 2 Observations: Reported
Galeras 1889 Jul 3 Unknown Confirmed 2 Observations: Reported
Purace 1885 May 25 Unknown Confirmed 3 Observations: Reported
Purace 1881 Unknown Confirmed 2 Observations: Reported
Purace 1878 Aug 31 Unknown Confirmed 2 Observations: Reported
Cumbal 1877 Dec Unknown Confirmed 2 Observations: Reported
Purace 1870 Oct Unknown Confirmed 2 Observations: Reported
Purace 1869 Oct 4 1869 Nov Confirmed 3 Observations: Reported
Galeras 1865 Oct 2 1870 Confirmed 3 Observations: Reported
Purace 1860 ± 9 years Unknown Confirmed 2 Observations: Reported
Purace 1847 Oct 27 1852 Confirmed 3 Observations: Reported
Ruiz, Nevado del 1845 Feb 19 Unknown Confirmed 3 Observations: Reported
Purace 1840 Unknown Confirmed 2 Observations: Reported
Galeras [1836] [Unknown] Uncertain  
Purace 1835 Jan 23 Unknown Confirmed 2 Observations: Reported
Galeras 1834 Unknown Confirmed 2 Observations: Reported
Ruiz, Nevado del [1833] [Unknown] Uncertain  
Ruiz, Nevado del 1831 Unknown Confirmed 2 Observations: Reported
Ruiz, Nevado del 1829 Jun 18 Unknown Confirmed 2 Observations: Reported
Galeras 1828 Oct 24 1834 Mar Confirmed 3 Observations: Reported
Ruiz, Nevado del 1828 Jun Unknown Confirmed 2 Observations: Reported
Purace 1827 Nov 18 Unknown Confirmed 2 Observations: Reported
Tolima, Nevado del 1826 May 1826 Jun 17 (in or after) Confirmed 2 Observations: Reported
Ruiz, Nevado del [1826] [Unknown] Uncertain  
Tolima, Nevado del 1825 Mar 2 (?) Unknown Confirmed 2 Observations: Reported
Galeras 1823 Jun 17 1823 Jun 24 Confirmed 2 Observations: Reported
Tolima, Nevado del 1822 Nov (?) Unknown Confirmed 2 Observations: Reported
Purace 1816 Unknown Confirmed   Observations: Reported
Ruiz, Nevado del 1805 Mar 14 Unknown Confirmed 2 Observations: Reported
Galeras 1796 Nov 1801 Confirmed 2 Observations: Reported
Galeras 1754 1756 Confirmed 2 Observations: Reported
Bravo, Cerro 1720 ± 150 years Unknown Confirmed 4 Correlation: Tephrochronology
Galeras 1670 1736 Confirmed 3 Observations: Reported
Galeras 1641 1643 Confirmed 3 Observations: Reported
Ruiz, Nevado del 1623 Unknown Confirmed 1 Observations: Reported
Galeras 1616 Jul 4 1616 Jul 4 Confirmed 3 Observations: Reported
Ruiz, Nevado del 1595 Mar 9 (in or before) Unknown Confirmed 4 Observations: Reported
Galeras 1580 Dec 7 1580 Dec 7 Confirmed 3 Observations: Reported
Ruiz, Nevado del 1570 Unknown Confirmed   Observations: Reported
Huila, Nevado del 1555 ± 5 years Unknown Confirmed   Observations: Reported
Ruiz, Nevado del [1541] [Unknown] Uncertain  
Galeras 1535 Unknown Confirmed 3 Observations: Reported
Ruiz, Nevado del 1350 (?) Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Bravo, Cerro 1330 ± 75 years Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Machin 1180 ± 150 years Unknown Confirmed   Isotopic: 14C (calibrated)
Bravo, Cerro 1050 ± 75 years Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Galeras 0890 ± 200 years Unknown Confirmed 2 Isotopic: 14C (calibrated)
Bravo, Cerro 0750 ± 150 years Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Machin 0750 (?) Unknown Confirmed   Isotopic: 14C (uncalibrated)
Ruiz, Nevado del 0675 ± 50 years Unknown Confirmed 3 Isotopic: 14C (uncalibrated)
Ruiz, Nevado del 0350 ± 300 years Unknown Confirmed 3 Isotopic: 14C (uncalibrated)
Tolima, Nevado del 0260 ± 150 years Unknown Confirmed 3 Isotopic: 14C (calibrated)
Purace 0160 BCE ± 50 years Unknown Confirmed   Isotopic: 14C (uncalibrated)
Tolima, Nevado del 0200 BCE ± 200 years Unknown Confirmed 3 Isotopic: 14C (calibrated)
Ruiz, Nevado del 0200 BCE ± 100 years Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Galeras 0490 BCE ± 100 years Unknown Confirmed 2 Isotopic: 14C (calibrated)
Tolima, Nevado del 0610 BCE ± 200 years Unknown Confirmed 3 Isotopic: 14C (calibrated)
Machin 0650 BCE (?) Unknown Confirmed   Isotopic: 14C (uncalibrated)
Bravo, Cerro 0730 BCE ± 75 years Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Ruiz, Nevado del 0850 BCE (?) Unknown Confirmed 4 Correlation: Tephrochronology
Santa Isabel 0850 BCE (?) Unknown Confirmed   Isotopic: 14C (calibrated)
Azufral 0930 BCE (?) Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Bravo, Cerro 1050 BCE ± 200 years Unknown Confirmed 4 Correlation: Tephrochronology
Galeras 1160 BCE ± 300 years Unknown Confirmed 2 Isotopic: 14C (calibrated)
Ruiz, Nevado del 1245 BCE ± 150 years Unknown Confirmed   Isotopic: 14C (uncalibrated)
Bravo, Cerro 1310 BCE ± 150 years Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Azufral 1650 BCE ± 150 years Unknown Confirmed   Isotopic: 14C (uncalibrated)
Azufral 1850 BCE (?) Unknown Confirmed   Isotopic: 14C (uncalibrated)
Tolima, Nevado del 1990 BCE ± 200 years Unknown Confirmed 5 Isotopic: 14C (calibrated)
Azufral 2095 BCE ± 100 years Unknown Confirmed   Isotopic: 14C (uncalibrated)
Machin 2100 BCE ± 200 years Unknown Confirmed   Isotopic: 14C (calibrated)
Machin 2240 BCE ± 300 years Unknown Confirmed   Isotopic: 14C (calibrated)
Dona Juana 2550 BCE ± 150 years Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Galeras 2580 BCE ± 500 years Unknown Confirmed 2 Isotopic: 14C (calibrated)
Machin 2650 BCE (?) Unknown Confirmed   Isotopic: 14C (uncalibrated)
Galeras 3150 BCE ± 200 years Unknown Confirmed 3 Isotopic: 14C (calibrated)
Tolima, Nevado del 3500 BCE ± 300 years Unknown Confirmed   Isotopic: 14C (calibrated)
Santa Isabel 3550 BCE (?) Unknown Confirmed   Isotopic: 14C (calibrated)
Machin 3800 BCE ± 150 years Unknown Confirmed   Isotopic: 14C (calibrated)
Bravo, Cerro 4280 BCE ± 150 years Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Santa Isabel 4800 BCE (?) Unknown Confirmed   Isotopic: 14C (calibrated)
Tolima, Nevado del 5160 BCE ± 200 years Unknown Confirmed   Isotopic: 14C (calibrated)
Tolima, Nevado del 5310 BCE ± 100 years Unknown Confirmed   Isotopic: 14C (uncalibrated)
Romeral 5390 BCE ± 350 years Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Santa Isabel 5500 BCE (?) Unknown Confirmed   Isotopic: 14C (calibrated)
Romeral 6510 BCE ± 200 years Unknown Confirmed 4 Isotopic: 14C (uncalibrated)
Ruiz, Nevado del 6660 BCE (in or before) Unknown Confirmed   Correlation: Tephrochronology
Galeras 7050 BCE ± 1000 years Unknown Confirmed   Correlation: Tephrochronology
Tolima, Nevado del 7800 BCE ± 300 years Unknown Confirmed 4 Isotopic: 14C (uncalibrated)

There are 35 photos available for volcanoes in Colombia.

Glaciated Tolima volcano is seen here looking south from the flank of Nevado del Ruiz. The summit consists of late-Pleistocene to Holocene lava domes and contains a crater 200-300 m deep. Holocene activity has ranged from moderate explosions to Plinian eruptions. A recent major eruption took place about 3,600 years ago and minor explosive eruptions took place in the 19th and 20th centuries.

Photo by Tom Pierson, 1985 (U.S. Geological Survey).
A gas plume rises above the glaciated Nevado del Huila Pico Central, seen here from the east in September 1996. Long-term, persistent, gas plumes occurred prior to the onset of eruptive activity in 2007. Before then, only a single 16th century eruption was known during historical time.

Photo by Bernardo Pulgarín, 1996 (INGEOMINAS, Colombia).
A dark, steaming lava seen from the east was emplaced during an eruption from Huila volcano that began in 2008. Pico del Sur lies at the left, with glacier-covered Pico Central at upper right and Pico Norte at far right. The lava dome straddled the summit ridge and descended opposite sides of the volcano. A major lahar in November 2008 swept down the Rio Paez, causing extensive damage. Long-term ome growth and periodic ash emissions continued.

Photo by Tom Pierson, 2010 (USGS, Cascades Volcano Observatory).
Two central lava domes of Cerro Machín volcano are seen here from the SW. A 3-km-wide caldera, whose rim is the horizontal change in slope across the center of the photo, opens towards the south. Late-Holocene eruptions produced block-and-ash flows that traveled to the west and south, beyond the caldera. Deposits from some of these eruptions form the eroded slopes in the lower part of the photo along the valley of the Toche River.

Photo by José Macías, 1996 (Universidad Autómona de México).
Romeral volcano forms the area in the center of this 24 January 2018 Sentinel-2 satellite image, NE of the city of Manizales (N is at the top; the image is approximately 19 km across). It produced two Plinian pumice eruptions that blanket areas NW of the volcano, and is located at the northern end of the Ruiz-Tolima volcanic chain.

Satellite image courtesy of Copernicus Sentinel Data, 2018.
Galeras, one of the most active volcanoes of Colombia, rises west of the city of Pasto. The high point is the eastern rim of a large caldera that is breached to the west and serves to funnel most of the eruptive products of the volcano away from the city. Larger explosive eruptions during historical time have produced pyroclastic flows that overtopped the caldera rim.

Photo by John Ewert, 1989 (U.S. Geological Survey).
An ash plume from the summit crater of Galeras volcano rises above the city of Pasto on May 5, 1989. Intermittent phreatic explosions ejected ash and blocks from the El Pinta vent beginning on February 19. Periods of stronger activity took place on March 26-27 and May 4-9. The May activity produced pyroclastic surges near the crater.

Photo by Norm Banks, 1989 (U.S. Geological Survey).
Cerro Negro de Mayasquer (Ieft) and snow-capped Volcán Chiles (right), seen here from the south, are twin volcanoes that straddle the Colombia-Ecuador border. Chiles volcano is of Pleistocene age, but has hot springs and an active hydrothermal system on its eastern flank. Cerro Negro de Mayasquer is a stratovolcano with a caldera open to the west. Andesitic and dacitic lava flows are of possible Holocene age. Solfataras are found on the shore of a small crater lake.

Photo by Minard Hall, 1985 (Escuela Politécnica Nacional, Quito)
Santa Isabel is a small glaciated volcano is seen here from its much larger neighbor to the NE, Nevado del Ruiz. Holocene lava flows fill SW and SE valleys. A small Holocene lava dome was emplaced about 10 km SW of the volcano.

Photo by Norm Banks, 1985 (U.S. Geological Survey).
Cerro Bravo in Colombia is seen to the north from the N flank of Nevado del Ruiz. The CB1 summit dome rises above an older dome and cone complex, probably produced during the CB7-CB5 eruptive periods. Below this, the remains of the pre-Cerro Bravo volcano encompass the Pleistocene Quebrada Seca caldera. Most of the Pleistocene lava flows in the foreground are associated with Nevado del Ruiz.

Photo by David Lescinsky, 1988 (University of Western Ontario).
On 13 November 1985 lahars traveled down the upper Guali River drainage on the N flank of Nevado del Ruiz, seen here descending diagonally from right of center to the lower left. Farmhouses are visible on the opposite side of the channel for scale. The lahars traveled down the Río Guali at velocities up to 17 meters/second to over 100 km from the volcano.

Photo by Tom Pierson, 1985 (U.S. Geological Survey).
A road cut exposes a pyroclastic flow deposit (left) overlying older granite (lower right). The dark zone dipping away from the front of the jeep, at the base of the pyroclastic flow deposit, are trees charred by the hot pyroclastic flow. This site is located along the road that connects the cities of Ibague and Cajamarco, close to the town of El Boqueron, about 12 km from Cerro Machín volcano.

Photo by José Macías, 1996 (Universidad Autómona de México).
The catastrophic 1985 eruption of Nevado del Ruiz began with moderate phreatic explosions on September 11. On November 13 a relatively moderate explosive eruption occurred, producing pyroclastic flows and surges that melted part of the summit icecap. These caused major lahars that devastated Amero and other towns on the flanks of the volcano, killing more than 23,000 people. Intermittent minor ash emissions, such as this one on November 28, and occasional stronger phreatomagmatic eruptions continued until July 1991.

Copyrighted photo by Katia and Maurice Krafft, 1985.
Nevado del Ruiz is a broad glacier-covered volcano that covers more than 200 km2. The modern cone consists of a cluster of lava domes constructed within the summit caldera of an older edifice. The ash-mantled summit is seen here from the ESE on 18 December 1985, a little more than a month after the catastrophic eruption of 13 November. The devastating 1985 lahars swept down four major river drainages that day and caused around 24,000 fatalities.

Photo by Norm Banks, 1985 (U.S. Geological Survey).
The summit of Cerro Negro de Mayasquer volcano is truncated by a caldera that is breached to the west. This view from the NW shows snow-capped Volcán Chiles at the upper left. Eruptive activity at these twin volcanoes has migrated to the west, with the most recent eruptions occurring from Cerro Negro de Mayasquer. A small crater lake is found at the bottom of the 900 x 1500-m-wide caldera. An eruption that was reported from the volcano in 1936 may actually have been from Reventador volcano to the SE.

Photo by Minard Hall, 1985 (Escuela Politécnica Nacional, Quito)
This aerial view of the Río Páez, with flow direction to the top, shows the path of the November 2008 lahars. The village at upper right is Mesa de Caloto, SSW of Huila. An eruption on November 20, 2008 destroyed part of the new lava dome, and hot material melted areas of the surrounding glacier and caused lahars in the Bellavista and Páez rivers, damaging infrastructure and destroying homes along the Río Páez.

Photo by Tom Pierson, 2010 (USGS, Cascades Volcano Observatory).
Snow-capped Puracé volcano has a 500-m-wide summit crater and is one of the most active volcanoes in Colombia. Frequent explosive eruptions in the 19th and 20th centuries have modified the morphology of the summit crater, with some of the largest occurring in 1849, 1869, and 1885.

Photo by Federmán Escobar Chávez, 2005.
The glacier on Nevado del Ruiz is seen here above the Azufrado valley on the NE flank. Debris avalanche deposits from an eruption roughly 3,100 years ago, and from the 1595 eruption, appear in the foreground. The major eruption about 3,100 years ago produced a large ashfall deposit, the debris avalanche, and associated lahars and pyroclastic surges. The 1595 eruption, the largest from Ruiz in historical time, was similar. Lahars in 1595 caused over 600 fatalities.

Photo by Jean-Claude Thouret (Université Grenoble).
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. It is seen here from the south on March 17, 1989, with steam clouds pouring from vents on the large central cone near the back headwall of the caldera, whose south rim forms the ridge in the foreground. Major explosive eruptions since the mid Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks.

Photo by Norm Banks, 1989 (U.S. Geological Survey).
Nevado del Huila is an elongate, N-S-trending glaciated edifice constructed within an old caldera, seen here from the SW. The northern peak (La Cuesta) is to the left and the lower southern peak to the right is Pico Central.

Photo by Juan Carlos Diago, 1995 (courtesy of Bernardo Pulgarín, INGEOMINAS, Colombia).
A large cone fills much of the large collapse scar at Galeras. It is seen degassing here on 18 March 1989 from the SE. The El Viejo flank crater can be seen near the center of the photo, with the Bastón fissure to the right, just below the rim of the main crater. The central cone has been the site of frequent eruptions since the time of the Spanish conquistadors.

Photo by Norm Banks, 1989 (U.S. Geological Survey).
A cluster of rounded boulders was deposited on a river terrace by a lahar in the Río Chinchina valley, 59 km WNW of the summit of Colombia's Nevado del Ruiz volcano on 13 November 1985. The boulders were carried within the lahar and deposited against the tree that served as an obstruction to flow. Note the mudline on the tree that marks the upper flow surface of the lahar.

Photo by Tom Pierson, 1985 (U.S. Geological Survey).
A plume rises from the summit crater of Nevado del Ruiz volcano on 10 December 1985. Pyroclastic surge and ashfall deposits from the 13 November eruption coat the glaciers. Glaciers on the upper NE-flank headwall of the Azufrado valley (foreground) were scoured by pyroclastic surges.

Photo by Tom Pierson, 1985 (U.S. Geological Survey).
Cerro Bravo is seen from the east. The summit dome was extruded during the most recent eruption and has a spine (a steep dome) near the top. An older lava dome and cone complex is situated to the left. Multiple collapse events sent block-and-ash flows down over lava flows (center) and onto the Plan de Arriba (lower left). The low tree-covered slope (left foreground) is the remnant of the pre-Cerro Bravo edifice that was destroyed by a Pleistocene caldera-forming event.

Photo by David Lescinsky, 1988 (University of Western Ontario).
Cerro Negro de Mayasquer is the youngest of a pair of twin volcanoes along the Ecuador-Colombia border. It is seen here from the Ecuadorian side on the south. The long ridge to the left of its summit is the rim of a horseshoe-shaped caldera that is breached to the NW.

Photo by Minard Hall, 1985 (Escuela Politécnica Nacional, Quito)
The Doña Juana complex in Colombia is shown in this September 2017 Planet Labs satellite image monthly mosaic (N is at the top; this image is approximately 8 km across). The summit area is shaped by a large scarp that has been infilled by lava domes, which have subsequently undergone collapse events to produce block-and-ash flow deposits.

Satellite image courtesy of Planet Labs Inc., 2017 (https://www.planet.com/).
A record of the 13 November 1985 eruption of Nevado de Ruiz was preserved in ice-rich levees of pyroclastic flows. This photo, taken a month later, shows parallel-bedded pyroclastic-surge deposits, composed of snow grains and tephra, which were deposited over a pre-existing ice at the bottom of the photo. The surge layers are overlain at the top by coarser-grained pyroclastic-flow deposits. The clast of glacial ice (located left of the upper part of the ice axe) was scoured and incorporated into the pyroclastic flow.

Photo by Tom Pierson, 1985 (U.S. Geological Survey).
Two weeks after the 13 November 1985 eruption, a plume rises from Las Arenas, the summit crater of Nevado del Ruiz. This view from the NNW shows pyroclastic surge and pyroclastic flow deposits mantling the summit icecap. Grooves descending the upper glacier surface were scoured by pyroclastic surges, which reached 5.5 km NW and NE of the summit. Melting of the summit icecap during the eruption led to devastating lahars that traveled as far as 100 km from the volcano and caused 24,000 fatalities.

Photo by Norm Banks, 1985 (U.S. Geological Survey).
On August 27, 1936, a vigorous explosive eruption took place from Galeras volcano. Photographs taken from Pasto show pyroclastic flows descending the NE flank to distances of 3-4 km from the summit. The timing of eruptive activity in 1936 is ambiguous, but evidence does exist for an eruption on February 9 that produced explosions, the ejection of incandescent bombs, and an ash plume.

Photo courtesy of Marta Calvache, 1936 (INGEOMINAS-Observatorio Vulcanológico del Sur).
Cumbal is the southernmost historically active volcano of Colombia. It is seen here from the north, with a young lava dome occupying the 150-m-wide summit crater. Flank craters, the youngest of which is Boca de Mundo Nuevo, have formed along radial fissures on the east and south flanks of the nearly symmetrical volcano. Eruptions from the upper east flank produced a 6-km-long lava field. Explosive eruptions in 1877 and 1926 are the only known historical activity from Cumbal.

Photo by Norm Banks, 1989 (U.S. Geological Survey).
Nevado del Tolima rises to the south above the forested mountains of the Central Cordillera of Colombia. The summit consists of a late-Pleistocene to Holocene lava domes that were associated with thick lava flows and extensive pyroclastic flow deposits. A major eruption took place about 3,600 years ago and moderate historical eruptions have occurred in the 19th and 20th centuries.

Photo by Norm Banks, 1895 (U.S. Geological Survey).
Azufral stratovolcano in southern Colombia, seen here from the SE, is also known as Azufral de Túquerres. It is truncated by a 2.5 x 3 km caldera containing a Holocene lava dome complex. A crescent-shaped lake, Laguna Verde, occupies the NW side of the caldera. Nearly a dozen lava domes are present, the latest of which were formed about 3600 years ago and have active fumaroles. The last known eruption of Azufral volcano took place about 1000 years ago.

Photo by Norm Banks, 1989 (U.S. Geological Survey).
Sotará in Colombia is shown in the center of this February 2020 Planet Labs satellite image monthly mosaic (N is at the top; this image is approximately 19 km across). The edifice formed within a 4.5-km-diameter caldera and has a collapse scarp open towards the SW, as well as several lava domes in the summit area. Thick lava flows and domes have been emplaced within the scarp.

Satellite image courtesy of Planet Labs Inc., 2020 (https://www.planet.com/).
The 1985 eruption of Colombia's Nevado del Ruiz volcano produced the deadliest lahars (volcanic mudflows) in recorded history. A relatively moderate explosive eruption melted parts of the summit icecap and sent lahars down four major drainages. The town of Armero, shown here, was destroyed by a lahar that had traveled 74 km east of the summit and exited a narrow canyon above the town in a 40-m-high wave. Three-quarters of the 28,000 inhabitants of Armero were killed because officials and residents were not prepared for the danger the volcano posed.

Copyrighted photo by Katia and Maurice Krafft, 1985.
The terraces along the Toche River are composed of thick pyroclastic flow deposits produced during Holocene explosive eruptions of Cerro Machín. The summit lava domes are seen on the horizon in this view from the NNW. This small but explosive volcano is located at the southern end of the Ruiz-Tolima massif.

Photo by José Macías, 1996 (Universidad Autómona de México).