Based on INSIVUMEH notifications, CONRED reported that Fuego’s ninth effusive eruption phase in 2017 began on 13 September. Explosions generated ash plumes that rose 1.2 km above the crater and drifted 15 km W and SW, causing ashfall in communities downwind including San Pedro Yepocapa (8 km N), El Porvenir (8 km ENE), and Sangre de Cristo (8 km WSW). Pyroclastic flows descended the Seca (Santa Teresa) ravine on the W flank. The eruptive phase ended about 35 hours later. INSIVUMEH noted that on 14 September, explosions generated ash plumes that rose 750 m and drifted 10 km W and SW. Shock waves from some explosions vibrated nearby structures. A lava flow was active in the Santa Teresa ravine. Explosions on 15 September produced ash plumes that rose as high as 750 m and drifted 5 km NW and SW. The lava flow was 300 m long. During 17-18 September ash plumes from explosions rose almost 1 km and drifted W and SW. Incandescent material was ejected 250 m above the crater rim, and caused avalanches of material around the crater area. Ashfall was reported in areas including Panimaché I and II (8 km SW), Morelia (9 km SW), and El Porvenir.

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