On 16 March INSIVUMEH reported an increased number of avalanches at Fuego, traveling down the Ceniza (SSW), Trinidad (S), and Las Lajas (SE) ravines. A 600-m-long lava flow advanced down the Trinidad drainage. Weak explosive activity accompanied lava effusion. There were 4-12 explosions per hour recorded at Fuego during 17-24 March, generating ash plumes that rose as high as 1.1 km above the crater rim and generally drifted 10-22 km S, SW, and W. Almost daily ashfall was reported in several areas downwind including Santa Sofía (12 km SW), Morelia (9 km SW), Panimaché I and II (8 km SW), Finca Palo Verde, San Pedro Yepocapa (8 km NW), Sangre de Cristo (8 km WSW), El Porvenir (8 km ENE), and La Cruz. Explosions sometimes produced shock waves that rattled nearby houses and were felt in communities within a 25-km radius. Incandescent material was ejected 100-400 m high and caused avalanches of material that occasionally traveled long distances (reaching vegetated areas) down the Seca (W), Taniluyá (SW), Ceniza, Trinidad, Honda, and Las Lajas ravines. Lava flows of variable lengths (400-1,000 m) descended the Trinidad and Ceniza ravines each day but were inactive by the evening of 23 March.

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)