Based on INSIVUMEH notices, CONRED reported that for a 30-hour period during 30 June-1 July activity at Fuego was at a high level, characterized by explosions, high-temperature pyroclastic flows (that began on 1 July), and ashfall. Ash plumes rose 4.8 km above the crater and drifted 25 km W and NW, producing ashfall in 22 local communities. The majority of material deposited by pyroclastic flows was in the Las Lajas drainage. Activity decreased later that day. During 4-6 July, INSIVUMEH reported that explosions produced ash plumes that rose as high as 800 m above the crater and drifted 8-10 km SW and W. Incandescent material was ejected 100 m high, and avalanches descended the Santa Teresa and other nearby drainages.

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)