No latest activity reported for San Jorge.

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.

Forjaz V H, Fernandes N S M, 1975. Geologic map of Ilha de San Jorge (Azores). {Servicos Geologicos Portugal}, 1:50,000 scale map with 32 p text (in Portuguese)

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

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

The remarkably linear island of San Jorge (Sao Jorge) is 54 km long and only 5 km wide. It was formed by fissure-fed eruptions beginning in the eastern part of the island. The western two-thirds of dominantly basaltic San Jorge contains youthful, fissure-fed lava flows resembling those on neighboring Pico Island. Subaerial lava flows issued from three locations above the south-central coast during 1580, producing lava flows that reached the sea. In 1808 a series of explosions took place from vents along the south-central crest of the island; one of these fed a lava flow that also reached the southern coast. Submarine eruptions were reported on several occasions from vents off the southern and SW coasts.