Kuwae

"Karua" redirects here. For places in Iran, see Karua, Iran. Submarine caldera between the Epi and Tongoa islands in Vanuatu

Kuwae is a submarine caldera between the Epi and Tongoa islands in Vanuatu. Kuwae Caldera cuts through the flank of the Tavani Ruru volcano on Epi and the northwestern end of Tongoa.

The submarine volcano Karua, one of the most active volcanoes of Vanuatu, is near the northern rim of Kuwae Caldera.

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Eruptive history

The Tongoa and Epi islands once formed part of a larger island called Kuwae. Local folklore tells of a cataclysmic eruption that split this island into two smaller islands with an oval 12 x 6:km caldera in between (but the story tells of an eruption south of Tongoa). Collapse associated with caldera formation may have been as much as 1100 m. Around 32–39:km³ of magma was erupted, making the Kuwae eruption one of the largest in the last 10,000 years.

In Antarctic and Greenland ice cores, a major eruption or series of eruptions is revealed as a spike in sulfate concentration, showing that the release in form of particles was higher than any other eruption since. Also, analysis of the ice cores pinpointed the event to late 1452 or early 1453. The volume of expelled matter is more than six times larger than that of the 1991 Pinatubo eruption and would have caused severe cooling of the entire planet the following three years. The link between the sulphur spike and the Kuwae caldera is questioned in a 2007 study by Károly Németh, et al. proposing the Tofua caldera as an alternative source candidate.

Recent activity

Since the eruption of c. 1452, Kuwae caldera has had several smaller eruptions with Volcanic Explosivity Indexes (VEIs) of 0 to 3. The latest confirmed eruption occurred on 4 February 1974 ± 4 days. It had a VEI of 0, and was a submarine eruption that formed a new island.

Islands have regularly formed in Kuwae caldera. The 1897–1901 eruption built an island 1:km long and 15 m high. It disappeared within 6 months. The 1948–1949 eruption formed an island and built a cone 1.6:km in diameter and 100 m high. That island also lasted less than one year. All the islands have disappeared from wave action and caldera floor movements. In 1959, the island reappeared for a short time and again in 1971. The last structure remained an island until 1975.

Activity at present at Kuwae is confined to intermittent fumarole activity, which stain the water yellow. Over the top of the volcan... ...read more

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