Report on Fuego (Guatemala) — 3 October-9 October 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 3 October-9 October 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, 3 October-9 October 2012. Smithsonian Institution and US Geological Survey.
14.473°N, 90.88°W; summit elev. 3763 m
All times are local (unless otherwise noted)
INSIVUMEH reported that on 3 October a hot lahar descended Fuego's Ceniza drainage (SSW), carrying logs, branches, and blocks. During 4-5 October explosions ejected incandescent tephra 75-150 m above the crater, producing ash plumes that rose 600-900 m and drifted 10 km N and NW. Explosions generated shock waves and vibrated houses in local communities. Avalanches descended the Ceniza and Taniluyá drainages (SSW).
On 7 October the seismic network detected increased activity characterized by tremor, low-frequency earthquakes, and a period of constant explosions. Rumbling was heard and shock waves were detected. Ashfall was reported in Panimache I and II (8 KM SW), Morelia (9 km SW), and Santa Sofia (12 km SW). Incandescent block avalanches originating from the crater descended the flanks. During 7-8 October explosions ejected incandescent tephra 75-150 m above the crater, and generated ash plumes that drifted 10 km S and SW. On 8 October a lava flow traveled 100 m down the Ceniza drainage, producing incandescent block avalanches from the flow front. Avalanches descended the Taniluyá drainage. Ashfall was reported in Panimache I and II, Morelia, and Asunción.
Geologic Background. 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.