In a special bulletin issued on 10 December, INSIVUMEH reported that during the previous few weeks activity at Fuego had remained high, characterized by ash emissions, frequent powerful explosions, and rumbling. On 10 December activity changed, with explosions being accompanied by lava fountains that rose 100-150 m above the crater. During 11-16 December explosions generated ash plumes that rose 650-850 m and drifted 15 km W, SW, S, and SE. Avalanches from lava flows descended drainages. Ashfall was reported in areas near the observatory, and in Morelia (9 km SW) and Panimaché (8 km SW). Incandescent material was ejected 100 m above the crater and explosions sometimes generated shock waves.

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)