A structural outline of the Yenkahe volcanic resurgent dome (Tanna Island, Vanuatu Arc, South Pacific)

• The paper deals with the structural evolution of the Yenkahe dome, which is a resurgent volcanic dome.
• This resurgent dome is located in the heart of the large Siwi caldera of Tanna Island (Vanuatu arc, Pacific ocean)
• The structural evolution of the dome shows both growth and collapse related to the migration of the underlying magma.
• A chronology between the main volcanic structures (Yasur volcano, caldera and Yenkahe dome) is provided.

A structural study has been conducted on the resurgent Yenkahe dome (5 km long by 3 km wide) located in the heart of the Siwi caldera of Tanna Island (Vanuatu arc, south Pacific). This spectacular resurgent dome hosts a small caldera and a very active strombolian cinder cone – the Yasur volcano – in the west and exhibits an intriguing graben in its central part. Detailed mapping and structural observations make it possible to unravel the volcano-tectonic history of the dome. It is shown that, following the early formation of a resurgent dome in the west, a complex collapse (caldera plus graben) occurred and this was associated with the recent uplift of the eastern part of the present dome. Eastward migration of the underlying magma related to regional tectonics is proposed to explain this evolution.