INSIVUMEH reported that during 6-7 December the number of explosions at Fuego increased to 3-5 per hour. Ash plumes rose 1 km above the crater and drifted 12 km W and SW, causing ashfall in areas downwind including Morelia (9 km SW), Santa Sofía (12 km SW), Panimaché I and II (8 km SW), El Porvenir (8 km ENE), and San Pedro Yepocapa (8 km N). Incandescent block avalanches reached vegetated areas. Activity continued at the same level through 12 December, although 4-6 explosions per hour were detected during 12-13 December. Ash plumes from explosions during 8-12 December rose as high as 1.1 km and drifted 12-15 km W, SW and S. Ash fell in the same areas downwind. During 8-9 and 11-12 December incandescent material was ejected 200 m above the crater, causing avalanches of material in the crater and towards the main ravines.

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)