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Vanuatu : " Islands of coral and ashes "

Tanna  |  Ambae  |  Karua  |  Ambrym  |  Lopevi  |  Gaua  |  Epi


© Vanair/Ph. Leloup.

The volcanoes of Vanuatu are located along a zone of convergence (subduction) of the Australian and Pacific Plates. They are part of the Pacific's "Ring of Fire", which accounts for 70% of the world's volcanic activity. The viscosity of the magma that underlies them gives them explosive characteristics. When a quantity of water is also present, this results in highly spectacular "hydro-magmatic" eruptions. In 1452, the cataclysmic explosion of Kuwae (between the islands of Epi and Tongoa) hurled more than 25 cubic kilometres of pulverized rock into the atmosphere.
Although it is now possible to predict the likelihood of an eruption, it is very difficult to pinpoint the exact timing of the event. Some of Vanuatu's volcanoes are in a state of permanent eruption (islands of Tanna and Ambrym), others, which have been dormant for a few decades, are now showing signs of renewed activity through gas emissions in their crater lakes (islands of Ambae and Gaua). Lopevi, the only Vanuatu volcano lacking a caldera, appears to follow a 15 to 20-year cycle of dormancy and activity. Submarine volcanoes, which will eventually give birth to islands, are evidenced on the surface of the ocean by a discoloration of the water. They may emerge for a time, subside, then reappear to form a new island.

Scientific advisers:
Michel Lardy
Michel.Lardy@noumea.ird.nc
Philipson Bani
Philipson.Bani@noumea.ird.nc

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