In a special notice on 20 March, INSIVUMEH reported that lava fountains rising 300-400 m above Fuego's crater during the night had decreased along with seismicity and rumbling noises. A lava flow was 1.5 km long in the Ceniza drainage (SSW), and ash plumes drifted SE and S. Explosions during 20-21 and 25-26 March generated ash plumes that rose 0.6-1.2 km and drifted SE, S, and W. Incandescent material was ejected from the crater. Lava flows remained active in the Ceniza drainage and traveled 600 m SW down the Taniluya drainage. Explosions produced ash plumes that rose 400-800 m above the crater and drifted E and W during 21-22 March, rose 300-500 m and drifted 5 km W and NW during 23-24 March, and rose 450 m and drifted W and NW during 24-26 March, which caused ashfall in Panimache I and II (8 km SW), Morelia (9 km SW), and Hagia Sophia.

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)