Candlemas Island

Geography & Climate

Candlemas Island is located in United Kingdom, within the South Sandwich Volcanic Arc of the broader Antarctic-Scotia Volcanic Regions. Situated at 57.08° S, 26.67° W in the Southern Hemisphere, the volcano lies within a subarctic climate zone. With a summit elevation of 550 meters above sea level, Candlemas Island is a moderately sized peak that remains accessible to hikers and researchers for much of the year. The volcanic landform is characterized as a composite, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

Candlemas Island sits in a subduction zone, where one tectonic plate dives beneath another, creating intense heat and pressure that generates magma. Subduction zones are responsible for many of the world's most explosive volcanoes and deadliest eruptions. For communities in United Kingdom near Candlemas Island, this tectonic setting means the volcano is capable of producing powerful explosive eruptions, pyroclastic flows, and lahars that can threaten populated areas within tens of kilometers of the summit. The dominant rock type is basalt / picro-basalt, a dark, fine-grained volcanic rock that forms from rapidly cooling, low-viscosity lava. Basaltic eruptions tend to be less explosive and produce fluid lava flows that can travel long distances. While less immediately dangerous than explosive eruptions, basaltic lava flows can destroy structures and infrastructure in their path, and volcanic gases released during these eruptions can affect air quality over a wide area.

Eruption History Summary

Candlemas Island has 4 recorded eruptions in the geological database, spanning from 1250 BCE to 1953 CE. The most powerful recorded event was an explosive event producing ash plumes up to several kilometers in 1911 CE, reaching VEI 2 on the Volcanic Explosivity Index. These eruptions span roughly 3,203 years of volcanic history. The most recent eruption in 1953 CE places this volcano within the modern era of volcanological observation.

GVP Reference Summary

The southern end of Candlemas Island consists of an eroded, glacier-covered basaltic stratovolcano cut by steep cliffs on the east. Lava flows along the cliff dip to the west, suggesting that the original summit vent was beyond the eastern shoreline. The northern end of the irregularly shaped, 6-km-long island consists of an andesitic-to-dacitic complex of scoria cones with radiating lava flows. These initially formed a separate island but now consist of a low attached platform that is estimated to be no more than a few hundred years old (LeMasurier and Thomson, 1990). Dark brown clouds mixed with white steam were reported in 1823 and 1911, but it has not been demonstrated which, if any, of the young north flank lava flows formed since the island was discovered in 1775. Geysers and hot pools have been observed on several occasions during the 20th century. Vindication Island, of possible Holocene age, is located 4.5 km west of Candlemas Island.

— Smithsonian Institution, Global Volcanism Program