A lake atop a rumbling volcano on the South Pacific island of Ambae has changed color from blue to bright red, puzzling scientists.
Mount Manaro, one of four active volcanos on the island nation of Vanuatu, has been showing signs of erupting for only the second time in 122 years.
“We are still ... trying to understand this change of color in the lake from blue to red,” Geology and Mines Department director Esline Garae said by telephone Monday from Vanuatu’s capital, Port Vila.
She said two scientists on Ambae Island were monitoring Lake Vui as well as seismic activity on the 5,000-foot Mount Manaro.
If the change of color “comes from new activity in the ground or just chemical change in the lake — these are two things I want to know from those guys before I can say anything” about the danger posed by the volcano, she said.
Mount Manaro last erupted in November 2005, forcing half the island’s 10,000 inhabitants to evacuate their villages. An 1884 eruption killed scores of villagers.
New Zealand volcanologist Brad Scott said Lake Vui’s color was “quite a spectacular red,” but what had caused it “is the $64,000-question.”
He said water samples from the lake would help determine what was happening in the crater and below it.
The color change could be a chemical process or gas from molten volcanic rock or something else coming into the lake, he said.
Three other volcanos in Vanuatu — Lopevi, Yasur and a two-crater volcano on Ambryn Island called Marum and Benbow — have spewed rocks, ash, smoke and steam in recent weeks.
Vanuatu, formerly the New Hebrides Islands, is made up of 13 main islands located about 1,400 miles east of Australia.