Research Cruise Will Allow Volcanologist to Make First-Ever Computer Simulations of Eruptions Under The Sea

BUFFALO, N.Y. -- The most volcanically active place on Earth produces eruptions that no human being has ever seen.

But Tracy Gregg, an assistant professor of geology at the University at Buffalo, is getting pretty close.

From now until early March, Gregg will be with other scientists on the Research Vehicle Atlantis, a National Science Foundation-supported cruise, exploring an area of the southeastern Pacific Ocean about 500 miles southeast of Easter Island.

About once a week, an 18-foot-long submersible vehicle called Alvin takes Gregg on dives, about two miles underneath the surface, to a place called a mid-ocean ridge, where the earth's tectonic plates are broken up. (To interview Tracy Gregg while she is at sea, contact Ellen Goldbaum at 716-645-2626 or goldbaum@buffalo.edu)

Gregg -- who is using email to keep in touch with her students at UB -- expects to use geologic samples and data obtained on the cruise to develop the first-ever computer simulations of undersea eruptions. The simulations will help her and other scientists begin to figure out how these eruptions contribute to the formation of the earth's crust and to the whole system of plate tectonics, as well as how the chemicals and sheer heat they unleash may impact climate change.

"This is the place where most of earth's volcanoes erupt," said Gregg. "We don't think about it because we don't see them, but they are very important because they are constantly putting heat and chemicals into the ocean."

Gregg believes she is the only scientist in the world who has dedicated a career to figuring out what an active undersea eruption looks like.

"I want to know what these eruptions are like, and what you would see if you witnessed one," she said. "How would it compare, for example, with a volcano on Hawaii?"

Unlike volcanologists who study eruptions on land and who can access detailed historical records about each eruption, Gregg has almost nothing to go on.

"It's as if I'm a detective and I'm trying to figure out who the murderer is, and all I have is a chalk outline of the body," she said.

During dives, Gregg enters a strange, dark world where the only light is that provided by Alvin. She keeps her eyes trained on the view outside the submarine's tiny porthole. She searches for interesting rocks, pieces of lava pillars -- beautiful, arched structures as high as 15 meters that form in layers after eruptions -- and other evidence that can be manipulated into the sub's basket to be studied back on the ship and in Gregg's lab at UB. Images of the ocean floor that are taken on dives will be digitized, allowing scientists to make accurate measurements of volcanic features.

Asked to make her best guess of what such an eruption would look like if the submarine became caught in one, Gregg responded that it would be quite dangerous, mostly because the divers wouldn't be able to see anything.

"The net effect would be like being caught in a blinding blizzard," said Gregg. "The intense heat from the lava would warm the overlying seawater, which would rise and violently stir up all the sediment down there, as well as bacteria hiding under the sea floor."

By reconstructing what undersea eruptions are like, Gregg hopes to help determine their impacts on the world, both above and below the ocean's surface. Effects of past eruptions may have been nearly apocalyptic, Gregg said.

"The asteroid that may have killed the dinosaurs was just one example of how a species became extinct," she said.

It may turn out that the intense heat and chemicals that undersea eruptions spew into the oceans and, subsequently, into the atmosphere could have caused mass extinctions as well, she said.

Gregg noted that there is some evidence that mass extinctions, including the one that occurred at the end of the Jurassic period, may have been caused by a massive increase in the rate of volcanic activity at mid-ocean ridges, which heated the oceans and caused ocean basins to become more shallow. That caused the oceans to flood much of the land that was the dinosaurs' habitat.

"Once we have an idea how big these eruptions are, then we can estimate how much heat they put into oceans and during what kind of time frame," she said.

During her trip, Gregg has been in regular communication with her students at UB, correcting homework assignments and providing fresh insights from her dives via email.

So far, Gregg has reported to them the unexpected discovery of a fresh lava flow and a brand-new hydrothermal site she and her shipmates dubbed "Bhudda's Place" after the submarine pilot's nickname. They also turned up evidence that a hydrothermal site that was teeming with sea life in 1993 is now nearly dead, typical of the short life span of hydrothermal vents that are nourished by the heat of individual volcanic eruptions.