Geodetic measurements used to estimate ice transfer during Bering Glacier surge

Abstract

The application of geodetic measurements to glacial research has found a new testing ground: near a surging Alaskan glacier. A set of geodetic measurements collected adjacent to the Bagley Icefield (Figure 1) and along the Gulf of Alaska (Figure 2) are being used to estimate the effects of the Bering Glacier surge that began in the spring of 1993. When ice is removed from a glacier's reservoir during a surge, its surface lowers by tens or hundreds of meters and ice is added to the receiving area, where it thickens and advances. The dramatic changes in a surging glacier's extent and thickness should result in elastic deformation of the solid Earth. At Bering Glacier, calculations show that ice transfer may have caused up to 17 cm of the solid Earth to subside. Although recent surges at the Bering and Variegated Glaciers have been well documented, little is known about most surges, particularly about what happens in the upper reaches of the glaciers.