INSIVUMEH and CONRED reported that on 12 October a new phase of activity began at Fuego, characterized by lava fountains rising as high as 400 m above the crater rim, avalanches of incandescent material down the W and SSW flanks, increased rumbling, and a lava flow traveling 1 km down the Santa Teresa (W) drainage. Very frequent explosions generated ash plumes that rose 850 m and drifted 12 km S and SE. On 13 October a steaming lahar descended the Ceniza (SSW) drainage, carrying blocks up to 2 m in diameter, and branches and tree trunks. During 13-16 October explosions (8-18 per hour) produced ash plumes that rose almost 1 km and drifted 8-12 km S, SW, and W. Ashfall was reported in areas downwind including Sangre de Cristo (8 km WSW), Finca Palo Verde, and Panimaché I and II (8 km SW). Incandescent material was ejected 150-200 m high, causing avalanches of material within the crater, though some of the avalanches traveled long distances, reaching vegetated areas. The lava flow on the W flank was still visible but by 14 October no longer active.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.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Coordinadora Nacional para la Reducción de Desastres (CONRED)