INSIVUMEH reported that 2-9 explosions per hour were recorded at Fuego during 24-31 May, generating ash plumes that rose as high as 1.1 km above the crater rim. The ash plumes drifted as far as 30 km in multiple directions, causing ashfall on most days in areas downwind including La Soledad (11 km N), Chimaltenango (21 km NNE), Parramos, Yepocapa (8 km N), Quisaché, Santa Isabel, La Rochela, El Zapote (10 km S), and La Trinidad (S). Ashfall was probable but not reported on three of the days. Daily shock waves rattled structures in communities around the volcano and occasional rumbling was heard. Block avalanches descended the upper flanks in all directions, but most commonly were visible in the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Honda, and Las Lajas (SE) drainages. Explosions ejected incandescent material 100-400 m above the summit on most days. Lahars descended the Ceniza and El Jute (SE) drainages during 27-28 May.

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)