The Capelinhos (from diminutive, which literally means "little cape") is a monogenetic volcano located on the western coast of Faial Island in the Azores. It is part of the larger volcanic complex of Capelo, which includes 20 scoria cones and lava fields that are aligned west-northwest to east-southeast from the Caldeira Volcano caldera. Although the name "Capelinhos" is associated with the volcano, it technically refers to the western cape of the parish of Capelo. It can be considered the westernmost point of Europe; there are more westerly islands in the Azores archipelago but they lie on the North American Plate.
A volcanic eruption lasted for 13 months, from September 27, 1957 until October 24, 1958, which may have been two overlapping volcanic eruptions. While enlarging the land by 2.4 km<sup>2</sup>, it spawned 300 seismic events, hurled ash 1 km, destroyed 300 houses in the parishes of Capelo and Praia do Norte and caused the evacuation of 2,000 people (emigration to the US and Canada). On October 25, the volcano entered a period of dormancy. It is a part of an active fissural volcanic complex which creates multiple seismic and volcanic events.
Geography and ecology
Capelinhos is located along the Capelo Volcanic Complex, that comprises a western area of fissural volcanism and historical eruptions leading away from the Cabeço do Fogo. The events that began in 1957 were an extension of the volcanic activity that abruptly ended at Costado da Nau, the escarpment at Ponta dos Capelinhos. Similar to the Horta Platform, the peninsula is consistent with the shapes and products resulting from Surtseyan, Strombolian and Hawaiian volcanic types. The formation is composed primarily of basaltic rocks, although, less frequently, Hawaiian hawaiitic rocks are observed.
Capelinhos is classified a Surtseyan eruption, since it was formed in the relatively shallow coast of the Faial seamount. However, , a volcanologist and full professor at the University of the Azores, defends that the type of eruption should have been designated as Capelinian as it pre-dates the eruption of Surtsey by five years and was studied both by Portuguese and foreign scientists.
Located at Cabeço Norte, a volcanic vent releases water vapour with temperatures between 180 °C and 200 °C from the volcano complex.
The geographer Christophe Neff is carrying field studies on the pioneer vegetation in the Capelinhos area since 1999. In a recently published paper in “Finisterra” he wrote in the English abstract of the paper “Fifty years after the Capelinhos eruption we cannot find any tree or bushes on the volcano.
IUGS geological heritage site
In respect of its importance in enhancing understanding of submarine volcanoes, Capelhinos was included by the International Union of Geological Sciences (IUGS) in its assemblage of 100 'geological heritage sites' around the world in a listing published in October 2022.
History
thumb|left|upright=1.7|Capelinhos Volcano, [[Faial Island, Azores, showing the lighthouse which marked the western coastal limit of Ponta dos Capelinhos]]
The Capelinhos eruption represented the first time that a submarine eruption was documented from beginning to end. Its location near an inhabited island with good communications meant it could be intensively studied. The first activities during the eruption were identified by engineer Frederico Machado, the Director of the District Public Works Department, his assistant engineer João do Nascimento and surveyor António Denis, under the authorization of the Civil Governor, Freitas Pimentel. The Director of the Observatory in Angra, Lieutenant-Colonel José Agostinho overflew the area, and Bernado Almada (at the Prince Albert of Monaco Observatory, in Horta) sent several bulletins relating the increased seismic activity of the area.
Between September 16 and 27, 1957, 200 earthquakes of intensity V (Moderate) on the Mercalli scale were registered. On September 23, the ocean waters off the coast of Ponte dos Capelinhos began to boil, and the first vapours were witnessed around 6:30 a.m. one kilometre northwest of the lighthouse. Following a night of torrential rains and ash (on or about 16 November) the explosive activity ceased, and an effusive lava phase began with more ash and explosive rock. By then the largest eruptive column had reached 1450 metres into the air, carrying with it ash from the northwest for a distance of 20 kilometres (6 December).