INSIVUMEH reported that eruptive activity continued at Fuego during 25 June-2 July. Daily explosions were recorded by the seismic network, averaging 1-7 per hour on most days, when counts were reported. The explosions generated gas-and-ash plumes that rose as high as 1.1 km above the crater rim and drifted as far as 30 km N, NW, W, and SW. The explosions produced block avalanches that descended various drainages including the Ceniza (SSW), Seca (W), Trinidad (S), and Las Lajas (SE), and Honda (E). Weak rumbling sounds and shock waves that rattled nearby houses and buildings within a 7-km radius were reported on most days. Ashfall was reported during the first half of the week in areas downwind including La Soledad (11 km N), Parramos (18 km NNE), Yepocapa (8 km NW), El Porvenir (11 km SW), Finca Palo Verde, Sangre de Cristo (8 km WSW), Quisaché (8 km NW), Pochuta (24 km WNW), Patulul (30 km W). Ashfall was forecast for areas downwind during the second half of the week. The explosions also ejected incandescent material up to 200 m above the summit on most days and crater incandescence could often be seen during the night or early mornings. On 28 June a lahar descended the Ceniza drainage, carrying tree branches, trunks, and blocks as large as 1.5 m in diameter.

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.

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