During 20-26 August, INSIVUMEH reported that weak to moderate explosions at Fuego expelled blocks up to 800 m above the rim. On most days white plumes rose 200-600 m above the crater and drifted SW and W and on 25 August the white plume rose to 4.2 km (13,800 ft) above the crater. Ash plumes rose 4.1-4.6 km (13,500-15,100 ft) a.s.l. and drifted 10-15 km NE, W, S and SW. Ashfall was reported in villages Morelia (9 km SW), Panimaché (8 km SW), Panimaché II, Sangre de Cristo (8 km WSW), and Hagia Sophia. On most days rumbling was heard around the volcano and rattled structures near the volcano on 24 August. On 21 and 25 August were jet engine like sounds lasting 1-4 minutes. Weak to moderate avalanches of blocks were channeled into the canyons Las Lajas (SE), Trinidad (S), Ceniza (SSW), Taniluyá (SW), Santa Teresa and Honda.

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)