Since 1770, Izalco has erupted at least 51 times. Izalco was once the most regularly active volcano in El Salvador, earning the title "lighthouse of the Pacific".
A small flank eruption in 1966 was the most recent activity. Temperatures of gases from f umaroles in the summit crater declined from 1964-1974.
Izalco is a small stratovolcano made of basalt.
Sources of Information:
Carr, M. J., Mayfield, D.G., and Walker, J.A., 1981, Relation of lava compositions to volcano size and structure in El Salvador: Journal of Volcanology and Geothermal Research, v. 10, p. 35-48.
Carr, M.J., and Pontier, N.K., 1981, Evolution of a young parasitic cone towards a mature central vent: Izalco and Santa Ana volcanoes in El Salvador, central America: Journal of Volcanology and Geothermal Research, v. 11, p. 277-292.
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.
Rose, W.I., and Stoiber, R.E., 1969, The 1966 eruption of Izalco volcano, El Salvador: Journal of Geophysical Research, v. 74, p. 3,119-3,130.
Simkin, T., and Siebert, L., 1994, Volcanoes of the World: Geoscience Press, Tucson, Arizona, 349 p.
Stoiber, R.E., Rose, W.I., Lange, I.M., and Birnie, R.W., 1975, The cooling of Izalco volcano (El Salvador): Geol. Jb. B 13, S. 193-205.