Glaciers, water under the glaciers, seismic activity and robotic rovers are all part of three National Science Foundation Polar Program grants awarded to Sridhar Anandakrishnan, professor of geosciences, Penn State. The grants, which total nearly a million dollars, are part of the American Recovery and Reinvestment Act funding.
Norway is the location for one of the grants that will try to establish a correlation between seismic activity on glacial surfaces and actual slip at the base of the glacier. While some scientists do use seismic measurements from the surface, it is currently not known how well these correlate with movement below. The Svartisen Ice Cap in Norway has tunnels in the rock beneath the glacier making access possible. The project will take measurements twice a year for two years.
"In April, before significant melting on the glacial surface, we will conduct pump tests that will bring the water pressure at the base of the glacier high enough to induce slipping," said Anandakrishnan. "We will measure seismic activity at the surface and in the tunnels."
During May and June, the researchers will measure natural seismicity. The results will provide a relationship between seismicity and slip and will be relevant to sliding ice masses regardless of their bed type, size or location.
The other two polar grants are part of WISSARD, the Whillans Ice Stream Subglacial Access Research Drilling that will assess the role of water beneath a West Antarctic ice stream using glaciologic, geologic, microbiologic, geochemical and oceanographic methods. One project concentrates on the stability of ice stream grounding zones -- the area where ice, ocean water and glacial and sea floor sediment interact.
The other project focuses on the role of active subglacial lakes in determining how fast the West Antarctic ice sheet loses mass to the ocean thus influencing global sea level changes. Because these under-glacier lakes have only recently been discovered, it is unknown what their contribution is to ice sheet stability and how they will influence the ice sheets under future global warming.