The current eruption from Fuego, located ~40 km WSW of the country's main airport (La Aura) and 17 km NE of the historic city of Antigua, has been ongoing since 2002. The Instituto Nacional de Sismologia, Vulcanología, Meteorología e Hidrologia (INSIVUMEH) monitors this volcano, providing regular observations. During the current reporting interval, 11 January 2008-12 January 2010, minor ash plumes were common, typically rising several hundred meters above the summit (tables 5 and 6). Some were incandescent. Plumes often drifted 5-15 km from the vent and residents in the region sometimes noted noise and shock waves. Observers occasionally saw avalanches and lahars, and sometimes an active lava flow traveled ~100 m from its vent. On 30 January 2009 observers saw incandescent material ejected 50-100 m above the crater and avalanches from the crater rim descended multiple ravines.

Table 5. Summary of reported activity at Fuego volcano for January 2008-December 2008. "--" indicates no data. Information courtesy of INSIVUMEH, Washington Volcanic Ash Advisory Center (VAAC), and HIGP Thermal Alerts System.

Table 6. Summary of reported activity at Fuego volcano for January 2009-January 2010. "--" indicates no data. Information courtesy of INSIVUMEH, Washington Volcanic Ash Advisory Center (VAAC), and HIGP Thermal Alerts System.

Observations. A report from Michigan Technological University described multi-instrument fieldwork during 9-21 January 2009 (Nadeau and Dalton, 2009), work often amid conditions of poor visibility. The authors also credited seven other people (from INSIVUMEH and PCMI; see Information Contacts) who participated in the campaign. One of the instruments deployed was an ultraviolet (UV) camera that enabled researchers to measure SO₂ emission rates with high temporal resolution. They also took concurrent seismic and infrasonic acoustic measurements, some mini-DOAS measurements, and they recorded their visual observations of volcanism. A similar campaign occurred in January 2008.

During this fieldwork, activity was dominated by passive degassing accompanied by intermittent tephra eruptions of variable size (figure 11). Explosions ranged from small puffs of ash that mixed with the passive gas plume to larger, convective columns with ejected bombs.

Figure 11. Passive degassing (left) and an explosion (right) at Fuego, December 2008-January 2009. From Nadeau and Dalton (2009).

During 9-21 January 2009, the UV camera was placed on Meseta ~1 km from the erupting vent (figures 12 and 13). An array seismo-acoustic stations was also deployed around the circumference of the vent for full azimuthal coverage. Thick clouds prohibited visibility on most days, resulting in collection of imagery on only 3 dates (12, 14, and 21 January). On 21 January several stationary mini-DOAS (differential optical absorption spectroscopy) scans of the passively degassed plume were also made for comparison with SO₂ retrievals from camera images.

Figure 12. Vertical aerial photo the Fuego summit (steaming, near the bottom) and Meseta edifice. Star indicates location of UV camera during field measurements. (inset) UV camera and plume as seen from measurement site. From Nadeau and Dalton (2009).

Figure 13. A map of SO2 concentration-pathlength created from UV imagery of Fuego during the 2009 campaign. Scale bar at bottom indicates concentration pathlength in colored versions (in units of ppm-m with highest values on the scale and in portions of the plume at ~1,000 ppm-m). From Nadeau and Dalton (2009).

Preliminary evaluation of camera-derived emissions at Fuego in January 2009 show decreases in SO₂ output prior to explosive events, and may indicate short-term sealing of the vent. Additionally, some small low-frequency seismic events without explosion signals in the acoustic record were associated with short-term increases in SO₂ output.

A paper presented by Lyons, Waite, and Rose (2009) suggests the potential to track activity of Fuego volcano using explosive energy partitioning. This has implications for monitoring and hazard prediction.

References. Nadeau, P., and Dalton, M., 2009, Report on UV camera field campaign, Fuego and Santiaguito volcanoes, Guatemala, December 2008-January 2009, unpublished informal report accessed January 2010 (URL: http://www.geo.mtu.edu/~panadeau/)

Lyons, J.J., Waite, G.P., and Rose, W.I., 2009, Variable explosive energy partitioning during open vent activity at Fuego volcano, Guatemala 2007-2009: Constraining explosion source processes and implications for monitoring, American Geophysical Union 2009 Fall Meeting Abstract V23D-2124.

Geological Summary. Volcán Fuego, one of Central America's most active volcanoes, is also one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between Fuego and Acatenango to the north. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at the mostly andesitic Acatenango. Eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.

Information Contacts: Instituto Nacional de Sismologia, Vulcanología, Meteorología e Hidrologia (INSIVUMEH) (National Institute of Seismology, Volcanology, Meteorology and Hydrology), Ministero de Communicaciones, Transporto, Obras Públicas y Vivienda, 7a. Av. 14-57, zona 13, Guatemala City 01013, Guatemala (URL: http://www.insivumeh.gob.gt/); Washington Volcanic Ash Advisory Center (VAAC) (URL: http://www.ospo.noaa.gov/Products/atmosphere/vaac/); MODIS/MODVOLC Thermal Alerts, Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Gregory Waite, John Lyons, Patricia Nadeau, Marike Dalton, and Joshua Richardson, Michigan Technological University, Department of Geological and Mining Engineering and Science, Houghton, MI, USA (URL: http://www.geo.mtu.edu/rs4hazards/); Kyle Brill, Jemile Erdem, and Jesse Silverman, PCMI (Peace Corps, Master's International Program), Michigan Technological University; Amilcar Cardenas (INSIVUMEH).