INSIVUMEH reported that during 9-16 May explosions at Fuego generated ash plumes that rose as high as 950 m above the crater rim and drifted 7-12 km W, SW, S, and E. Ashfall was reported in San Pedro Yepocapa (8 km N), Morelia (9 km SW), Santa Sofía (12 km SW), and Panimache I and II (8 km SW) during 9-12 May. On 14 May a hot lahar descended the Río Ceniza (SSW) and Santa Teresa (W) drainages, carrying blocks 2 m in diameter, branches, and tree trunks. Sounds from colliding blocks were audible more than 1 km away, and steam plumes rose from the lahar. During 14-16 May avalanches descended the Ceniza and Las Lajas (SE) drainages, and gas emissions rose from pyroclastic-flow deposits in the ravines.

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)