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There are no activity reports for San Jorge.
Available Weekly Reports
There are no Weekly Reports available for San Jorge.
Summary of eruption dates and Volcanic Explosivity Indices (VEI).
|Start Date||Stop Date||Eruption Certainty||VEI||Evidence||Activity Area or Unit|
|[ 1964 Feb 18 ]||[ Unknown ]||Uncertain||0||Off SW coast|
|1902 May 7||1902 May 8||Confirmed||0||Historical Observations||Subm. vent ca. 20 km SW of Terceira|
|1808 May 1||1808 Jun 10||Confirmed||1||Historical Observations||Sao Jorge|
|1800 Jun 24||1800 Jun 25||Confirmed||2||Historical Observations||Subm. vent ca. 20 km SW of Terceira|
|1757 Jul 9||1757 Jul 10||Confirmed||0||Historical Observations||Off south coast of Sao Jorge|
|1580 May 1||1580 Aug 30 (?)||Confirmed||3||Historical Observations||Sao Jorge (SW side)|
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.