During a trek on the Banks Islands in November 2017, Thomas BOYER explored an active area on the island of Vanua Lava.
In the photos below, we can visualize the geographical location of this area explored by the red mark.
We left Lanetak village with our local guides who know the area very well.
After crossing the forest, we arrive at this area with many fumaroles and sulfur deposits and we establish our camp.
We are located just below the historic craters of the island in this area filled with fumaroles, sulfur deposits and some solfatares from which a small stream was born.
Indeed, at the foot of this collapse zone, there are many sources and ponds with outgassing, the water is warm and the whole forms a small stream.
On the slopes of this collapse, there are many fumaroles with a release of water vapor and sulfur gas at the origin of sulfur deposits observed.
Sulfur crystallizes giving very beautiful needles. The gases escaping from these structures are sometimes very hot, they contain water vapor as well as hydrogen sulphide at the origin of these crystallizations when it oxidizes in the air.
On this thermal image, one can observe the high temperature of the gases escaping from these vents.
By gaining height, we observe a small lake with opalescent waters that we will observe.
On the shores of this lake, the vegetation fallen into the water is covered with a white coating that does not adhere to its support.
The water is opalescent and seems to contain the same white substance.
On the banks of this small lake, many sources seem to feed it, the water is warm and it evacuated by a spillway located in front of our position.
Thomas Boyer will take a sample of this water for analysis.
This area has an important activity that is difficult to date but which should be monitored.