Ambae / Aoba:
The island of Ambae (1496 m) corresponds to the emergent part of the voluminous volcanoes of the archipelago's active volcanoes (3900 m high from the ocean floor and about 2500 km3 in volume, making it a volcano altogether exceptional).
Two concentric calderas crown it, the innermost including three lakes, including the Voui acid crater lake (2.1 km in diameter) installed in the current crater of the volcano. Recent volcanic activity is marked by the eruption of November 2005 - January 2006, which resulted in the formation of an island 500 m in diameter and 50 m high inside the Voui, A sharp change in the color of the lake in May 2006. A strong degassing still exists in the middle of the newly formed island.
Ph. Bani et al. (2012) A. Beaumais et al. (2013).
(Vui lake, mai 2017, Th. Boyer)
Change in color of Lake Vui in May 2006.
The approach of this lake is difficult and perilous. (Mai 2017, Th. Boyer)
Large deposits of ignimbrite show cataclysmic eruptions. (Mai 2017, Th. Boyer)
On December 5, 2005, thousands of people were displaced, at the initiative of the Vanuatu government, following major explosions during the eruption of the Lombenben volcano.
More than two thousand tons of SO2 were released every day. The crater being located in the middle of Lake Voui, an increase in eruptive activity causes fear of a part of the waters of the lake. The millions of liters of acid water of this lake constitute a great threat to the local population situated below, on the coastal strip.