"The behavior has stayed remarkably constant, which is actually quite unusual for volcanoes," said Nial Peters, lead study author and a geophysicist at the University of Cambridge in the United Kingdom.
The new study also reports other intriguing behavior in the bubbling lake. For instance, the lava heaves in concert with its 10-minute gas cycle, its surface rising and falling by about 6 to 10 feet (2 to 3 m), Peters said. And lava cooling on the lake surface cracks and flows outward at a speed that matches the fluctuating gases. "Think of the lake as a bowl sitting on top of a pipe, and as fresh batches of magma come up into the bottom they rise up and spread out," Peters told Live Science's Our Amazing Planet. "That's what we see in the velocity flow outward from the center of the lake. It looks like a thick, treacly liquid, which is gradually convecting."
Lava lakes are rare — there are only four long-lived lakes on Earth, because the volcano must continuously supply lava to the surface. There are lakes at Erebus, Hawaii's Kilauea volcano, Ethiopia's Erta Ale volcano, and Nyiragongo volcano in the Democratic Republic of the Congo. (Photos: The World's Five Most Active Volcanoes)
Erebus volcano's magma is a rare type called phonolite, up to 100 times more viscous than the basalt at Kilauea in Hawaii and Erta Ale in Ethiopia. Though Erebus is the only active volcano with phonolite lava, its twin is Kilimanjaro in the East African Rift, Kyle said. Both are steep-sided, cone-shaped phonolite volcanoes rising from rifts, where the Earth's crust is stretching apart. Looming up from Ross Island, Erebus is visible from McMurdo research station and New Zealand's Scott Base.
The long-term observations at Erebus volcano's lava lake are among the only rigorous studies of these valuable windows into magmatic systems, said Matt Patrick, a volcanologist with the U.S. Geological Survey's Hawaii Volcano Observatory, who was not involved in the study.
"The Peters paper represents a big step in understanding active lava lakes, in large part due to the uniquely detailed observations they have made of the lava lake activity," Patrick said.
With their bounty of data, the members of the Erebus team are now moving toward their next big goal: explaining how the volcano works.
"That's the $64,000 dollar question," Kyle said of the oddly predictable plumbing.