Report on Fuego (Guatemala) — 1 August-7 August 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 1 August-7 August 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Fuego (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 1 August-7 August 2012. Smithsonian Institution and US Geological Survey.
14.473°N, 90.88°W; summit elev. 3763 m
All times are local (unless otherwise noted)
In a special bulletin on 3 August, INSIVUMEH reported a new phase of activity at Fuego, characterized by increased seismicity and degassing sounds. Incandescent tephra was ejected 200 m high and a lava flow traveled 500 m down the SW flank into the Taniluya drainage. Pyroclastic flows likely descended the SE and SW flanks. During 4-7 August explosions produced ash plumes that rose 200-400 m above the crater and drifted NW and W. Lava flows traveled 250-300 m down the Taniluyá drainage. Detached blocks from the lava-flow front traveled down the flanks to the vegetated area. Blocks also traveled down the Ceniza drainage (SSW). At night during 5-6 August explosions ejected incandescent tephra 100 m above the crater.
Geologic Background. Volcán Fuego, one of Central America's most active volcanoes, is one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between 3763-m-high Fuego and its twin volcano to the north, Acatenango. 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 Acatenango. In contrast to 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.