Report on Fuego (Guatemala) — 16 August-22 August 2017
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 August-22 August 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, 16 August-22 August 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 the eighth effusive episode at Fuego in 2017 began on 20 August. Constant explosions generated ash plumes that rose 2.3 km above the crater and drifted more than 50 km W and SW. Ashfall was reported in areas downwind including Panimaché I (8 km SW), Morelia (9 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Sangre de Cristo (8 km WSW), and Yepocapa (8 km WNW). Two lava fountains, each 300 m high, fed lava flows that traveled 1.4 km SSW down the Ceniza ravine and 1.2 km W down the Seca (Santa Teresa) ravine. Incandescent block avalanches occurred throughout the crater. Some explosions generated shock waves that rattled nearby structures. Seismicity decreased on 21 August. Weak explosions generated ash plumes that rose 1 km and drifted 20 km. Suspended ash from explosions and pyroclastic flows was visible. The lava flows had lengthened 200 m in the Ceniza ravine and 100 m in the Santa Teresa ravine. The report warned that pyroclastic flows were concentrated in the Santa Teresa ravine, possibly filling the drainage with deposits (similar to activity from 5 May) and increasing the chances for lahars. Ash fell in San Pedro Yepocapa (8 km N) and Chimaltenango (21 km NNE). On 22 August INSIVUMEH noted that after 48 hours the effusive episode was over. Explosions produced ash plumes that rose 1.2 km and drifted SW, and continued to vibrate nearby structures. Incandescent material was ejected as high as 200 m above the crater rim.
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.