By implementing seismic technology, researchers found a way to track for the first time water flow through the inside of ocean-bound glaciers.
“Meltwater from Glaciers ending on dry land is easy to track,” says Timothy Bartholomaus, postdoctoral fellow at the Institute for Geophysics, University of Texas at Austin, expaining that it is done by measuring how much water flows from the glaciers into meltwater rivers. “But most of the world’s biggest glaciers end in the ocean, making their melt previously impossible to determine,” he says.
While conducting research monitoring iceberg calving—the shedding by a glacier of large, Titanic-sinking chunks of ice—Bartholomaus and his team installed seismometers all over glaciers.
“We kept seeing variations of the background vibrations that were more intense during the summer,” says Bartholomaus. The variations reminded him of the ones made by landlocked glaciers at that time of year
During the winter, the glacier stops melting, and the river turns off, says Bartholomaus. During the summer, as the heat increases, an internal trickle of water begins, creating an intricate network of plumbing inside the glacier. “As summer continues, the plumbing gets more efficient,” says Bartholomaus. He compares it to “water hammer” in hydraulic engineering, likening the glaciers to the old radiators that pulse, shake and bang. “Those same kinds of hydraulic principles of engineering are taking place within these glaciers,” says Bartholomaus.
The vibrations of this plumbing system taking shape inside glaciers ending at sea was similar to that of glaciers on land, which allows Bartholomaus to compare the vibrations and track the ramping up of the water flow.
The next project is to pin a measured flow in gallons per minutes to the vibrations of water flow on land and use it to determine a GMP in all glaciers.
“It would give us much more data to track changes in our climate,” says Bartholomaus.