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Below is a summary of eruption dates and Volcanic Explosivity Indices (VEI).

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Geist D, Howard K A, Jellinek A M, Rayder S, 1994. The volcanic history of Volcan Alcedo, Galapagos Archipelago: a case study of rhyolitic oceanic volcanism. {Bull Volc}, 56: 243-260

Geist D, Howard K A, Larson P, 1994. The generation of oceanic rhyolites by crystal fractionation: the basalt-rhyolite association at Volcan Alceda, Galapagos Archipelago. {J Petr}, 36: 965-982

Goff F, McMurtry G M, Counce D, Simac J A, Roldan-Manzo A R, Hilton D R, 2000. Contrasting hydrothermal activity at Sierra Negra and Alcedo volcanoes Galapagos Archipelago, Ecuador. {Bull Volc}, 62: 34-52

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. {IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior}.

McBirney A R, Williams H, 1969. Geology and petrology of the Galapagos Islands. {Geol Soc Amer Mem}, 118: 1-197

Naumann T, Geist D, 2000. Physical volcanology and structural development of Cerro Azul volcano, Isabela Island, Galapagos: implications for the development of Galapagos-type shield volcanoes.. {Bull Volc}, 61: 497-514

Richards A F, 1962. Archipelago de Colon, Isla San Felix and Islas Juan Fernandez. {Catalog of Active Volcanoes of the World and Solfatara Fields}, Rome: IAVCEI, 14: 1-50

Simkin T, 1980. . (pers. comm.)

Alcedo is one of the lowest and smallest of six shield volcanoes on Isabela Island. Much of the flanks and summit caldera are vegetated, but young lava flows are prominent on the northern flank near the saddle with Darwin volcano. Alcedo is the only Galápagos volcano known to have erupted rhyolite as well as basalt, producing about 1 cu km of late-Pleistocene rhyolitic tephra and lava flows from several vents late in its history. Recent faulting has produced a moat around part of the 7-8 km caldera floor, which is elongated N-S and appears to be migrating to the south. Fewer circumferential fissures occur on Alcedo than on other western Galápagos volcanoes. An eruption attributed to Alcedo in 1954 (Richards, 1957) is more likely to have been from neighboring Sierra Negra (Simkin 1980, pers. comm.). Photo-geologic mapping of Alcedo by K. A. Howard (pers. comm.) revealed only one flow on October 30, 1960 photographs that does not appear on May 30, 1946 photos. That is near Cartago Bay, low on the SE flank, rather than the 610-m, NE-flank elevation listed for the 1954 eruption. An active hydrothermal system is located within the caldera.