Report on Fuego (Guatemala) — 14 November-20 November 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 November-20 November 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Fuego (Guatemala). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 14 November-20 November 2018. Smithsonian Institution and US Geological Survey.
14.473°N, 90.88°W; summit elev. 3763 m
All times are local (unless otherwise noted)
INSIVUMEH and CONRED reported that activity at Fuego increased on 18 November, heralding the fifth effusive phase of 2018. Incandescent material was ejected 200-300 m above the crater rim and a lava flow in the Ceniza (SSW) drainage reached 2.5 km in length. Avalanches of material from the lava flow reached vegetated areas. Explosions occurring at a rate of 8-17 per hour generated ash plumes that rose at least 1.2 km and drifted 20-25 km W and SW. Ashfall was reported in areas downwind including Morelia (9 km SW), Santa Sofia (12 km SW), Sangre de Cristo (8 km WSW), Panimaché I and II (8 km SW), and Finca Palo Verde. Volcanic material also accumulated in the Taniluyá (SW) and Seca (W) drainages causing increased risk of avalanches. Later that day explosions became stronger, and incandescent material was ejected 400 m high. Ashfall continued to be reported in local communities. CONRED reported that a portion of National Route 14 was closed, and evacuations began in some local areas.
Strombolian activity continued to intensify on 19 November with stronger explosions and increased seismicity. Incandescent material was ejected as high as 1 km above the crater. Ash plumes rose as high as 3.2 km and drifted 20-60 km W, SW, and NE. Pyroclastic flows descended the Seca drainage, and, along with ash emissions from the crater, caused ashfall in multiple areas including Santa Sofia, Sangre de Cristo, Panimaché I and II, and Finca Palo Verde. The lava flow in the Ceniza drainage advanced to 3 km long and produced avalanches from the flow front. Avalanches of tephra also descended the Seca, Ceniza, Taniluyá, Las Lajas, and Honda (E) drainages, reaching vegetated areas. CONRED noted that 3,925 people had been evacuated.
INSIVUMEH noted that the effusive phase was over at 1800 on 19 November, having lasted for 32 hours. Explosions continued during 19-20 November, generating ash plumes which rose 0.8-1 km and drifted 10-15 km NW, W, and SW. Ash fell in areas downwind including El Porvenir (8 km ENE), Morelia, Santa Sofia, Sangre de Cristo, Panimaché I and II, and Finca Palo Verde. Incandescent material was ejected 100-300 m high, casing avalanches, some that traveled long distances. Some explosions generated shock waves that rattled nearby structures.
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.