The Coriolis Troughs of the New Hebrides subduction zone are among the youngest backarc rifts in the world.
They reach depths of >3 km, despite their small size (<100 km in length and only 25–45 km wide) and their proximity to the arc front (∼50 km).
How do we ‘see’ #volcanoes in the deep sea? Check out this gorgeous bathymetry of #Vanuatu submarine back-arc, from https://t.co/rV6m7Chf5e pic.twitter.com/YXb7yEB4Xk
— GAC-VIP Division (@gacvip) July 18, 2017
The narrow, deep graben morphology is characteristic of magma-deficient arc rifts in the early stages of backarc extension, where the rate of extension and subsidence exceeds the magmatic input.
Unexpectedly, the youngest graben, the Vate Trough, contains a centrally-located 1000-m tall and 14-km wide shield volcano with a large, 5×8 km breached summit caldera.
Source: Earth and Planetary Science Letters
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