Colima Volcano

Colima Volcano (Volcan de Fuego de Colima, 3860m) is the historically active and most southerly of three N-S-aligned andesitic volcanic edifaces of the Colima Volcanic Complex (CVC). Immediately north of Colima Volcano lies Nevado de Colima (4240m), followed by the older and heavily eroded El Cantaro Volcano (2900m). Volcan Colima is the most active volcano in Mexico with numerous eruptions mentioned in historical records, including powerful Sub-Plinian to Plinian eruptions, most recently in 1818 and 1913. Numerous less powerful explosive eruptions and periods of intracrater dome growth or extrusion of viscous lava flows, often accompanied by pyroclastic flows have also been documented. The CVC Complex is also notable for a propensity for relatively frequent sector collapses (12 during the last 45000 years), resulting in voluminous debris avalanches extending for many kilometers into the surrounding countryside and destroying everything in their path. Further such events would likely be associated with heavy casualties, since over 400000 people live within 40 km of the volcano.

Colima erupting viewed from south	Colima Summit	Eruption at dawn

Breton-Gonzalez et al. 2002 (J. Volc. Geotherm. Res. 117, p.21-46) traced back the eruptive history of Colima Volcano in historical records from the year 2000 to 1519. Although the exact nature of the eruption and its magnitude are difficult to establish for older eruptions, it is clear that powerful eruptions occurred in 1576, 1585, 1606, 1613, 1622, 1690, 1711, 1744, 1769, 1770. Numerous smaller eruptions were also reported between these events. More recently, powerful Subplinian-Plinian eruptions were recorded in 1818 and 1913, both of which are now considered to mark the end of approximately 100 year eruptive cycles (Luhr and Carmichael, 1990. J. Volc. Geotherm. Res. 42, p.235-260). It is possible that the 1606 and 1690 events also marked the end of such cycles and a similar cycle is nearing its end, so a renewed powerful eruption could occur in the next years.

This assumption is based on correlation of eruptive history with petrological characteristics of deposits. The andesitic lavas of the last 2 cycles have about 60% silicate, whilst the products of the climactic eruptions terminating each cycle are more basic with as little as 57.9% silicate. Trending of eruptive products in intra-cycle eruptions appears to show increasing basicity as the cycle nears completion. A similar trend towards more basic products was observed by Luhr and Carmichael when studying products erupted during the present (4th) cycle between 1961 and 1988. However, the trend was not continuous and lower horneblend contents in the eruptive products suggest that water content is significantly lower in the magmas of the present cycle than during previous ones. This in turn meaning that the cycle-ending eruption may occur later and/or be weaker in magnitude since exsolution of water vapour from the magma is one driving force of eruptions. Savov et al. 2008 (J. Volc. Geotherm. Res. 174, p.241-256) studied samples from the vulcanian eruption series of 1999-2005 (which involved over 16000 eruptive events, produced up to 11km high ash clouds and 5km long pyroclastic flows; summary of events in Table 1 of Savov et al.) and confirmed the trend towards more basic eruptates, however stating that the results may reflect increasing magma temperature since 1961. Further, it was pointed out that the magma continued to arrive at the surface in a degassed state (as lacking in vesicles). Hence, it is difficult to predict when the present cycle will come to an end (or indeed if a further cycle like the previous ones is taking place).

Luhr and Carmichael also describe the basic chronology of each cycle. Following cycle ending-eruptions, the deep summit crater formed is gradually filled with a new lava dome. About mid-cycle the dome starts to overflow the crater and viscous lava flows may descend the flanks. Phases of at times powerful explosive activity may become more frequent towards the end of a cycle. Over 2900 explosive eruptions occurred between 1893 and 1905, with the most powerful recorded between 1900 and 1903. Interestingly, the series of vulcanian eruptions occuring from 1998-2005 correlates closely to the timing of the series observed towards the end of the 3rd cycle.

Colima complex from E. Fuego on left, Nevado on right	Fuego de Colima in evening light	Explosive eruption

	Fuego de Colima in evening light, Nevado de Colima behind

The 1913 eruption has been studied in detail (see Saucedo et al. 2010. J. Volc. Geotherm. Res. 191, p.149-166; ref. therein). The eruption started on January 17 and reached its climax on January 20 when a Plinian column over 20 km high was sustained for over 4 hours. Three sequential eruption phases have been defined. Initially, a series of powerful explosive eruptions occurred, forming several kilometer high ash clouds and causing failure of parts of the summit lava dome. Pyroclastic flows and surges occurred, initially mainly on the south flank of the volcano with flow distances of up to 4km. Subsequently, flow activity shifted more to the north and culminated in a large flow containing about 34% reddish non-juvenile andesite fragments derived from the summit region. This flow appears to mark the destruction of the remaining plug on top of the conduit. In the second phase (from 04:00 to 10:30am on 20 January), a series of Vulcanian explosions with increasing intensity was observed, accompanied by column-collapse pyroclastic flows and surges, extending as far as 11km from the summit. Deposits now included significant amounts of pumice and scoria suggesting that fragmentation of magma from below the dome was already occuring as the final remnants of the dome were blown away by the explosive activity, accompanied by significant pyroclastic flows. After a brief pause in activity, increasingly powerful explosions occurred, leading up to the generation of a Plinian eruption column from about 11:30am onwards. The column reached a maximum height of over 20km and was sustained over a period of from 4-8 hours (data and eyewitness reports are inconsistent) before it collapsed, leading to extensive pyroclastic flows. Powerful explosive activity continued with eruptions producing dense cauliflower-like clouds that collapsed over the flanks of the volcano generating scoria-rich pyroclastic flows reaching up to 15km from the summit. Some of the associated surges inundated the flanks of Nevado de Colima up to a height of 4000m. A large proportion of forest on the flanks of the volcano was directly destroyed or set on fire. Increasingly sporadic explosions and smaller pyroclastic flows continued until January 14 when the eruption finally came to a conclusion. The ash clouds produced during the climax of the eruption were carried northeast by the wind and coated Ciudad Guzman in over 15cm of ash, resulting in numerous roofs collapsing. Small amounts of ash were reported as far as 725km away. The Plinian phase produced about 1.4 cubic kilometers of deposits (0.57 cbm DRE), the subsequent pyroclastic flows up to 0.1 and the total volume erupted was about 1.66 cubic km.

The frequency of sector collapses at Colima is unusually high, with at least 12 occurring in the last 45000 years and at least 9 occuring at Volcan de Colima alone in the last 22000 years. Each resulted in voluminous debris avalanches extending for many kilometers into the surrounding countryside and burying everything in their path. As activity continues at the complex, the next such event is probably just a matter of time. The structures of both Nevado de Colima and Colima Volcano have been shaped by such events. The eastward-oriented Atentique caldera (technically a large collapse scar), hosts the summit structure of N. d. Colima, and present-day Colima Volcano is nested in an about 4km wide southwest-oriented caldera, the northern walls of which are still exposed between Nevado de Colima and Colima Volcano. This caldera is thought to have formed about 4300 years ago, when about 10 cubic km of the top of the then about 4100m high volcano (Paleofuego) collapsed, resulting in deposits covering at least 1550 square kilometers and extending up to 70km from the volcano (Luhr and Prestegaard, 1988. J. Volc. Geotherm. Res. 35, p.335-348). The area inundated included present day Colima City and numerous smaller towns and villages. It is unlikely that anyone in the area would be able to survive a repeat of such event. Further, it remains to be seen if precursory activity (such as the deformation of the edifice preceeding the Mt St Helens eruption in 1980, or a general increase in eruptive activity) would occur, allowing evacuations to take place. Present-day Colima has nearly reached the calculated height of the volcano prior to the 4300 YBP collapse. Smaller but nevertheless devastating collapses occur more frequently. A SW-oriented collapse, known as the La Lumbre-Los Ganchos debris avalanche, with a volume of about 1.7 cubic km occurred about 3600 years ago (Cortes et al. 2010. J. Volc. Geotherm. Res. 197, p.52-66). An area of 48 sq. km was covered. The deposit is coated with a pyroclastic flow deposit suggesting it was associated with a magmatic event and thus likely similar to the famous Mt St Helens and Bezymianny eruptions in recent times. Parts of the flow ran up against by the 1900m high Cerro Grande limestone formation, blocking the Armeria River and forming a temporary lake. Failure of the deposit dam led to a secondary debris flow, devastating areas up to 20 km downstream. The largest known collapse at the CVC also involved a primary debris flow, followed by a dam formation and failure event, with the combined deposits covering an area of at least 2200 sq. km, and extending for 120km from the Nevado de Colima edifice from where it originated about 18500 years ago (Capra and Macias, 2002. J. Volc. Geotherm. Res. 117, p.213-235).

The S-SW orientation of most sector collapses at Volcan Colima is explained by a number of factors. The CVC lies in the Alceseca-Atenquique Graben (/Trench) which is formed by a local extensional regime pulling in NW and SE directions either side of the graben. This appears to favour collapses along the axis of the graben. Collapses are favoured in a southwesterly direction since the adjoining Nevado de Colima edifice acts as a butress, stabilizing the N flank of Volcan Colima. Further, it is possible that intrusion of magma is occurring predominantly in the southern part of the edifice and thereby causing destabilization of the southern flank (Luhr and Prestegaard, 1988. J. Volc. Geotherm. Res. 35, p.335-348). This would correlate to continued southward migration of the active part of the complex. Indeed, there are already two extruded structures on the southern flank of Volcan Colima, known as Los Hijos del Volcan (Children of the Volcano). Graben-oriented collapses of twin-volcanoes can be observed at other sites, such as at Popocatepetl-Iztaccihuatl in Mexico or Fuego-Acatenango in Guatemala.

A number of hazards are associated with CVC, even when the volcano is not erupting. Sector collapses may not necessarily be directly associated with eruptive events and increased levels of rainfall-induced lahars may occur for years following eruptive events as loose volcanic deposits are swept off the flanks of the volcano. In cases of extreme rainfall, volcaniclastic debris flows involving older volcanic material may occur. The Atenquique formation, a horseshoe-shaped depression formed by a pre-historic sector collapse and encompassing the summit of Nevado de Colima directs much of the rain falling on the volcano into the Atenquique ravine. On October 16, 1955, following 3 days of intense rainfall corresponding to nearly twice the monthy average for the month, a huge flood entrained volcaniclastic debris to form a devastating debris flow which flowed through the town of Atenquique, destroying numerous buildings and killing 23 inhabitants (Saucedo et al. 2008. J. Volc. Geotherm. Res. 173, p.69-83). The town had been established in 1946 around a paper milling facility by the river. The flow had a 60% sediment concentration w/w, and formed an on average 4 meter thick deposit which covered over 1.2 square km. Historical records show that devastating floods have occurred in several drainages of the CVC complex (see e.g. Table 1 of Saucedo et al.). For example, the City of Colima was inundated and severely damaged in at least 1573, 1626, 1865, 1884, and 1959 with some damage also occuring in 2001. Over 325 lives were lost in 1906 in flooding that also affected Colima and swept away the Hydroelectric Power Station in El Remate. The 1959 flood killed over 300 people, largely in the town of Minatitlan which was destroyed.

Daytime activity 04.02.2015 - 09.02.2015

	Eruption in late afternoon with Fuego slightly shrouded in cloud

	Eruption thrusting dark ash cloud into ash from earlier eruption

	Eruption with straight column due to lack of wind

Poweful explosion partially obscured by cloud	S-shaped ash cloud due to wind conditions	Ash cloud viewed from East

Eruption at dawn with visible incandescence	Similar eruption during daylight

Late 2014 Lava flow deposit on W flank still sporadically degassing

Nighttime activity 04.02.2015 - 09.02.2015

	Selection of Nighttime Eruptions

Powerful Nighttime Eruption (1/7)	(2/7)	(3/7)	(4/7)

(5/7)	(6/7)	(7/7)

Monitoring Flight on 09.02.2015

View from NW	View from NW	View from N

	View from SE

View from NW	View from SE

	Summit crater complex viewed from North

View from NE	View from E	View from E

Thermal Camera Images (courtesy of N. Varley)	Thermal Camera Images (courtesy of N. Varley)

Additional Images From 25.10.2015 - 01.11.2015

A second visit was made to Colima in October 2015, since the ash emitted semed to be highly conducive to the build-up of static charges in the ash cloud, with the result being visible discharges, also referred to as volcanic lightning. The lightning discharges are shown in the timelapse animations near the top of the page.

View of Colima from SW	Eruption viewed from SW

Warning sign East of Colima	Nighttime Eruption viewed from East

Visitor Information

Visitors can either fly directly to Colima airport, or via the larger airport in Guadelajara, from which Colima city is an about 3 hour drive (using the faster Toll roads). The landscape around the volcano has many deep valleys and thus driving around the volcano takes many hours. The best easily accessible viewpoints are to the south of the volcano. It is possible to drive up Nevado de Colima, yet no views of the active Fuego de Colima are possible from the road or parking area. Several hours of hiking are necessary to reach observation points. Observation is often hampered by clouds or fog in the afternoon or evening and haze may become a problem in the dry season. During the wet season, roads may be damaged by lahars following heavy rainfall.

Whilst Mexico has generally quite a poor reputation for security, the area around Colima is considered relatively safe. Restaurants and shops are found in various villages around the volcano and Colima and Ciudad Guzmann both have large shopping Malls.

Village East of Colima volcano	Southern Viewpoint (12km from summit)

Lahar Damage due to Hurrican Patricia in 2015	Lahar Damage due to Hurrican Patricia in 2015

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