Report on Fuego (Guatemala) — 5 July-11 July 2017
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 5 July-11 July 2017
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2017. Report on Fuego (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 5 July-11 July 2017. 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 4-7 explosions per hour at Fuego during 6-7 July generated ash plumes that rose as high as 950 m above the crater and drifted 6-10 km SW and W. Incandescent material was ejected 100-200 m above the crater rim, and caused avalanches of material that traveled down the Ceniza (SSW), Taniluyá (SW), Santa Teresa (SW), and Trinidad (S) drainages. Later on 7 July the rate of explosions increased to 7-10 per hour. During 7-9 July ash plumes rose as high as 1.1 km and drifted 15 km W, causing ashfall in Santa Sofía (12 km SW), Morelia (9 km SW), Panimaché I and II (8 km SW), El Porvenir (8 km ENE), Sangre de Cristo (8 km WSW), and possibly San Pedro Yepocapa (8 km N). A lava flow traveled 1.5 km down the Las Lajas (SE) drainage. On 11 July INSIVUMEH declared that the 6th eruption of the year with lava effusion was in progress. Explosions generated ash plumes that rose as high as 1.3 km above the crater and drifted 35 km W, and shock waves rattled nearby structures. Ash fell in areas including Morelia, Panimache, Santa Sofía, El Porvenir, and Sangre de Cristo. Two lava flows were fed by lava fountains 150-250 m high; one lava flow traveled 2.3 km down the Las Lajas drainage and another traveled 1.7 km down the Santa Teresa (SW) drainage. Later that day INSIVUMEH reported that the 31-hour-long eruption had ended. A few weak-to-moderate explosions continued, generating ash plumes that rose 850 m and drifted 6 km W.
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.