In a special bulletin from 21 December, INSIVUMEH reported the beginning of the 16th Strombolian episode in 2016 at Fuego. Ash plumes rose 1.5 km above the crater and drifted 18 km S, SW, W, and NW, and ashfall was reported in nearby areas including Morelia (9 km SW), Santa Sofía (12 km SW), Panimaché I and II (8 km SW), and Sangre de Cristo (8 km WSW). Lava fountains rose 200-300 m above the crater and fed three lava flows: the first traveled 2.5 km W down the Santa Teresa drainage, the second traveled 2 km SW down the Taniluyá Canyon, and the last traveled 1.8 km SE down the Las Lajas drainage. Shock waves from explosions rattled structures within a 12-km radius. During 24-27 December weak explosions generated ash plumes that rose 450-750 m and drifted 5-10 km W and SW.

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)