No latest activity reported for Sete Cidades.

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.

Booth B, Croasdale R, Walker G P L, 1978. A quantitative study of five thousand years of volcanism on Sao Miguel, Azores. {Phil Trans Roy Soc London}, Ser A, 288: 271-319

Martins J A, 1982. Excursion guide for field trip V1, Island of Sao Miguel. {Proc Internatl Symp Activity Oceanic Volc, Archipelago Univ Azores}, 3: 315-328

Moore R B, 1983a. Preliminary geologic map of Sete Cidades volcano, Sao Miguel, Azores (1:18,000). {U S Geol Surv Open-File Rpt}, 83-742

Moore R B, 1990. Volcanic geology and eruption frequency, Sao Miguel, Azores. {Bull Volc}, 52: 602-614

Moore R B, 1991. Geologic map of Sao Miguel, Azores. {U S Geol Surv Map}, I-2007

Neumann van Padang M, Richards A F, Machado F, Bravo T, Baker P E, Le Maitre R W, 1967. Atlantic Ocean. {Catalog of Active Volcanoes of the World and Solfatara Fields}, Rome: IAVCEI, 21: 1-128

Newhall C G, Dzurisin D, 1988. Historical unrest at large calderas of the world. {U S Geol Surv Bull}, 1855: 1108 p, 2 vol

Zbyszewski G, Moitinho de Almeida F, Veiga Ferreira O da, Torre de Assuncao C, 1958. Geologic map of Sao Miguel (Azores). {Servicos Geologicos Portugal}, two 1:50,000 scale maps with 22 and 37 p texts (in Portuguese)

Sete Cidades volcano at the western end of Sao Miguel Island contains a 5-km-wide summit caldera, occupied by two caldera lakes, that is one of the scenic highlights of the Azores. The steep-walled, 500-m-deep caldera was formed about 22,000 years ago, and at least 22 post-caldera eruptions have occurred. A large group of Pleistocene post-caldera trachytic lava domes, lava flows, and pyroclastic-flow deposits is found on the western-to-northern flanks. A nearly circular ring of six Holocene pyroclastic cones occupies the caldera floor. These have been the source of a dozen trachytic pumice-fall deposits erupted during the past 5000 years. Sete Cidades is one of the most active Azorean volcanoes. Historical eruptions date back to the 15th century and have occurred from within the caldera and from submarine vents off the west coast.