In a special report, INSIVUMEH reported a significant increase in activity at Fuego on 30 December. A series of pyroclastic flows descended the Las Lajas and El Jute drainages on the SE flank, and a dense ash plume rose 5 km and drifted 20 km W. Ashfall was reported in multiple communities on the flanks, including Panimache I and II (8 km SW), Morelia (9 km SW), and Santa Sofía (12 km SW). In another special report issued on 4 January, INSIVUMEH noted that dense ash plumes rose as high as 7 km and drifted over 40 km W, SW, S, and SE. Some explosions generated shock waves that vibrated nearby houses. Ash fell in Panimache I and II, Morelia, Santa Sofía, El Porvenir (8 km ENE), La Rochelle, and Osuna. Lava fountains rose 400-500 m above the crater and fed 2.5-km-long lava flows in the Santa Teresa (SW), Trinidad (S), and Las Lajas (SE) drainages. Collapses of parts of the cone generated pyroclastic flows that descended the Las Lajas, El Jute, and Trinidad drainages. By the next day activity had decreased; explosions produced ash plumes that rose 550 m and drifted 12 km S, SE, and SW. The lava flows were no longer active.

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.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)