Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) reported that eruptive activity continued at Fuego during 17-24 September. Daily explosions were recorded by the seismic network, averaging 3-11 per hour when reported. The explosions generated gas-and-ash plumes that rose as high as 1.1 km above the crater rim and drifted as far as 30 km in multiple directions. Weak rumbling sounds were reported on most days and shock waves were sometimes detected in local areas. The explosions ejected incandescent material generally up to 200 m above the summit on most days though material was ejected 300-400 m above the summit during 21-22 September. The explosions often produced avalanches of material that descended the flanks, sometimes reaching vegetated areas. Ashfall was reported in areas downwind including Panimaché I and II (8 km SW), El Porvenir (10 km S), Santa Sofia (12 km SW), Morelia (10 km SW), Los Yucales (12 km SW), and Yepocápa (8 km NW) during 17-18 September and in La Rochela (8 km SSW), Finca Ceilán (9 km S), El Zapote (10 km SSE), and El Rodeo during 21-22 September. Ashfall was forecast for areas downwind on the other days.

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)