CONRED and INSIVUMEH reported that during 4-6 October increased explosive activity (8-12 explosions per hour) at Fuego generating ash plumes that rose as high as 1.3 km above the crater. Ash plumes drifted more than 20 km S, SW, and W; ashfall was reported in areas downwind including Panimaché I and II (8 km SW), Santa Sofía (12 km SW), Morelia (9 km SW), and El Porvenir. Incandescent material rose 300 m above the crater, and avalanches of material traveled as far as 1.5 km W down the Seca (Santa Teresa) ravine and SSW down the Ceniza ravine. Shockwaves vibrated local structures. An average of 4-6 explosions per hour were detected during 7-8 October. Ash plumes rose around 1 km and drifted 12 km W, NW, and N. Incandescent material was ejected 150 m above the crater, causing avalanches that were confined to the crater. Ash fell in local communities including San Pedro Yepocapa (8 km N), Sangre de Cristo (8 km WSW), and La Soledad. Vulcanian explosions during 8-9 October produced ash plumes that rose 1 km and drifted 15 km SW, W, and NW, again causing ashfall in Panimaché, Santa Sofía, Morelia, El Porvenir, San Pedro Yepocapa, and Sangre de Cristo. Block avalanches traveled 2 km down the flanks.

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)