INSIVUMEH reported that during 29 December-3 January explosions from Fuego generated ash plumes that rose 400-800 m above the crater; the plumes usually drifted SSW and WSW, but on 30 December they drifted 10 km E and NW. During the week explosions generated shock waves and rumbling sounds that were detected 10 km away. House windows and roofs vibrated in nearby villages. Incandescence emanated from the crater at night, and avalanches traveled SW into the Taniluyá and Ceniza drainages, and S in the Santa Teresa drainage during 29 December-2 January. On 3 January the wind lifted ash to an altitude of 500 m. Based on information from satellite observations, the Washington VAAC reported that a possible ash plume drifted SE on 3 January. That same day, information from INSIVUMEH and satellite imagery indicated small emissions that rose to an altitude of 4.9 km (16,000 ft) a.s.l and drifted SE.

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.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center (VAAC)