On 10 January, INSIVUMEH reported an increase in the number and magnitude of explosions from Fuego since mid-December. During the previous three days explosions had produced ash plumes that rose 1 km above the crater and drifted 25 km mainly S and SW, and remained in the atmosphere for several hours. INSIVUMEH recommended that civil aviation authorities restrict flying within 25 km S and SW of Fuego. During 13-14 and 16-18 January explosions produced ash plumes that rose 200-500 m above the crater and drifted SW, E, and NE. Rumbling was heard and shock waves were detected. At night during 13-14 January, explosions ejected incandescent material as high as 75 m above the crater.

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)