Seismicity and Eruptive Activity of Fuego Volcano, Guatemala: February 1975 - January 1977
Digital Object Identifier (DOI)
We examine seismic and eruptive activity at Fuego Volcano (14°29′N, 90° 53′W), a 3800-m-high stratovolcano located in the active volcanic arc of Guatemala. Eruptions at Fuego are typically short-lived vulcanian eruptions producing ash falls and ash flows of high-alumina basalt. From February 1975 to December 1976, five weak ash eruptions occurred, accompanied by small earthquake swarms. Between 0 and 140 (average ≈ 10) A-type or high-frequency seismic events per day with M > 0.5 were recorded during this period. Estimated thermal energies for each eruption are greater by a factor of 106 than cumulative seismic energies, a larger ratio than that reported for other volcanoes.
Over 4000 A-type events were recorded January 3–7, 1977 (cumulative seismic energy ≈ 109 joules), yet no eruption occurred. Five 2-hour-long pulses of intense seismicity separated by 6-hour intervals of quiescence accounted for the majority of events. Maximum likelihood estimates of b-values range from 0.7 ± 0.2 to 2.1 ± 0.4 with systematically lower values corresponding to the five intense pulses. The low values suggest higher stress conditions.
During the 1977 swarm, a tiltmeter located 6 km southeast of Fuego recorded a 14 ± 3 microradian tilt event (down to SW). This value is too large to represent a simple change in the elastic strain field due to the earthquake swarm. We speculate that the earthquake swarm and tilt are indicative of subsurface magma movement.
Citation / Publisher Attribution
Journal of Volcanology and Geothermal Research, v. 21, issues 3-4, p. 277-296
Scholar Commons Citation
Yuan, Annette T.E.; McNutt, Stephen R.; and Harlow, David H., "Seismicity and Eruptive Activity of Fuego Volcano, Guatemala: February 1975 - January 1977" (1984). School of Geosciences Faculty and Staff Publications. 252.