From late August through late September the summit was usually obscured by clouds. When the volcano was visible (26-29 August, 4-7 and 11-13 September), only steaming took place, from some or all of several vents high on the E and ENE flanks. Two fissures, of approximately equal depth, emitted steam S of and slightly below the top of the summit cone. Although winds for the past 2 months have frequently blown from Fuego toward Antigua, no ashfalls have occurred there during that time, in contrast to earlier, more active periods.

Unusually heavy rains have caused landslides and widespread flooding throughout Guatemala, resulting in many deaths, major crop losses, and closures of main road and rail transportation routes. Secondary mudflows formed from tephra on Fuego's flanks have been particularly destructive, as far downstream as the coastal plain.

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.

Information Contacts: P. Newton, Antigua.