Sete Cidades is a stratovolcano located in Portugal, standing at an elevation of 842.0 meters with its tectonic setting situated in a rift zone on oceanic crust less than 15 kilometers deep. According to the Smithsonian Global Volcanism Program record, the volcano has a confirmed total of 16 eruptions spanning from deep antiquity into the late 19th century.
The historical and prehistoric record incorporates events evaluated through different evidentiary methods, ranging from scientific tephrochronology correlation for ancient periods to direct human observations for later centuries. Recorded activity levels vary significantly across these events, with measured Volcanic Explosivity Index (VEI) values reaching up to 4.0.
Overview of Recorded Eruptions
The documented timeline of Sete Cidades begins in the 31st century BCE and stretches forward across multiple centuries. Out of the 16 confirmed eruptions in the official record, 14 have associated VEI values. The earliest recorded event took place around 3050 BCE at the Seara Cerrado da Ladeira activity area, carrying a VEI of 4.0 determined through tephrochronology correlation.
Activity continued intermittently across centuries. For instance, an eruption occurred in the southeast caldera floor (Lagoa Rasa) around 380 CE with a VEI of 4.0 and an estimated start year uncertainty of 300 years. As historical documentation improved, physical reporting became available. An eruption on the southwest side of the caldera (Caldeira Seca) was reported in the year 1444 CE with a VEI of 4.0. Later events shifted in scale and location, such as a VEI 2.0 eruption on the west flank at Pico das Camarinhas in 1713 CE.
Latest Recorded Activity
The latest confirmed eruption in the official database started on July 2, 1880, with a VEI of 0.0. The activity area for this final recorded event is noted in the record as an uncertain submarine vent off Sao Miguel. No subsequent eruptions are logged in the structured collection.
Frequently asked questions
How many eruptions have been recorded at Sete Cidades?
The official record contains 16 confirmed eruptions for Sete Cidades.
When did the earliest recorded eruption take place?
The earliest recorded eruption in the official data occurred around 3050 BCE.
When was the most recent recorded eruption?
The latest confirmed eruption in the official record started on July 2, 1880.
What is the largest recorded VEI for this volcano?
The largest recorded eruptions at Sete Cidades reached a Volcanic Explosivity Index (VEI) of 4.0.
Sources and further context
Official datasets support the event-specific facts.