Pacaya is a complex volcano, consisting of an older stratovolcano, domes, flows, tephra, and the modern basaltic stratovolcano.
Most of the complex has formed in the last 23,000 years.
Pacaya has erupted at least 23 times since 1565. Little is known about the early historic eruptions due to the remote location of the volcano.
Vertical aerial photograph of Pacaya in 1962.
Vertical aerial photograph of Pacaya. In 1962, collapse near the summit of the volcano formed a pit crater. The pit crater has been the focus of more recent volcanic activity and a cone is growing in the crater.
Since 1965, Pacaya has been erupting nearly continuously. The style of eruption alternates between strombolian and plinian. Hundreds of explosions occur each day at Pacaya. Strombolian eruptions throw incandescent bombs hundreds of meters into the air and produce small aa flows. This photo shows aa flows on Pacaya on November 11, 1993.
Close-up of aa flows on Pacaya.
Pacaya and the Big Dipper.
Small explosive eruption at Pacaya, December 1986. Photograph by Bruce Nelson and Mike Lyvers.
Image Source: Steve O'Meara of Volcano Watch International
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External Links about Pacaya...
Sources of Information:
Bardintzeff, J.M., and Deniel, C., 1992 Magmatic evolution of Pacaya and Cerro Chiquito volcanological complex, Guatemala: Bulletin of Volcanology, v. 54, p. 267-283.
Conway, F.M., Diehl, J.F., and Matias, O., Paleomagnetic constraints on eruption patterns of the Pacaya composite volcano, Guatemala: Bulletin of Volcanology, v. 55, p. 25-32.
Eggers, A.A., Chavez, D., 1979, Temporal gravity variations at Pacaya volcano, Guatemala: Journal of Volcanology and Geothermal Research, v. 6, p. 391-402.
Feldman, L.H., 1993, Mountains of fire, lands that shake: Earthquakes and volcanic eruptions in the historic past of central America (1505-1899): Culven City, California, Labyrinthos, 295 p.
McClelland, L., Simkin, T., Summers, M., Nielsen, E., and Stein, T.C., 1989, Global Volcanism 1975-1985: Englewood Cliffs, New Jersey, Prentice Hall, 655 p.
Simkin, T., and Siebert, L., 1994, Volcanoes of the World: Geoscience Press, Tucson, Arizona, 349 p.