During 23-29 July INSIVUMEH reported moderate to strong explosions at Fuego, with incandescent blocks being expelled 100-200 m above the crater accompanied by moderate to dark gray ash 400-600 m above the crater that drifted NW, W, and SW. On most days avalanches moved down the flanks. Columns, described as containing ash on 24 and 28 July, rose 4-4.6 km (13,100-15,100 ft) a.s.l. and drifted 8-12 km NE, NW, W, and SW. A weak white fumarolic plume rose above Fuego’s summit crater on 27-28 July. During 26-27 July, rumbling was heard up to 15 km away. Ashfall was reported most days in nearby areas, including the Santa Teresa, Taniluya, Ceniza, and Trinidad drainages, and at the Observatory, Morelia, Hagia Sophia, Ingenio los Tarros, Panimaché, Santa Sofia, Yepocapa, and Finca La Conchita.

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)