Instituto Nacional de Sismología, Vulcanologia, Meteorologia e Hidrología (INSIVUMEH) reported that eruptive activity continued at Fuego during 31 July-6 August. Daily explosions were recorded by the seismic network, ranging from 2 to 10 explosions per hour. The explosions generated gas-and-ash plumes that rose as high as 4.8 km above the crater rim and drifted as far as 30 km SW and W. The explosions produced block avalanches that descended the Ceniza (SSW), Santa Teresa (W), Seca (W), Taniluyá (SW), and Las Lajas (SE) drainages. On most days the explosions also ejected incandescent material 100-300 m above the summit, which was observed at night and early morning. The activity was often accompanied by weak-to-moderate rumbling sounds, shock waves, and sounds similar to a turbine engine lasting a few minutes at a time. Ashfall was reported on 31 July and 1 August in areas downwind including Panimaché I and II (8 km SW), Finca Paloverde (10 km SW), El Porvenir (10 km S), Santa Sofia (12 km SW), Sangre de Cristo (10 km SW), Morelia (10 km SW), Los Yucales (12 km SW), and other nearby communities. Ashfall was forecast for areas downwind on some of the other days.

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)