Massive iceberg breaks off Antarctic glacier
Thursday, February 16, 2017, 6:03 PM – NASA satellites have spied a massive chunk of ice that broke off an Antarctic glacier at the end of January.
The Pine Island ice shelf has calved several huge icebergs over the past few years, and the latest has been described by NASA as “about a kilometer or two” of ice, breaking off sometime between January 24 and January 26.
The space agency posted “before and after” pictures on its Earth Observatory website on Wednesday, based on images taken from the Operational Land Imager (OLI) on the Landsat 8 satellite.
As large as it the iceberg is, it actually pales in comparison to others that have broken off in recent years from the glacier, which receives about 79 cubic kilometres of ice per year from the West Antarctic ice sheet.
In 2015, the glacier calved an iceberg about ten times larger than the one from January, about 583 square kilometres in all, and Ohio State University glaciologist Ian Howat, who said in NASA release that January’s event was likely an “aftershock” of the earlier, larger calvings.
“Apparently, there are weaknesses in the ice shelf—just inland of the rift that caused the 2015 calving—that are resulting in these smaller breaks,” he said.
NASA says they’ve detected several more rifts on the Pine Island glacier not far from where it meets the sea, and they expect they will contribute to future break-offs before long.
“[It] fits into the larger picture of basal crevasses in the center of the ice shelf being eroded by warm ocean water, causing the ice shelf to break from the inside out,” Howat says.
SOURCE: NASA Earth Observatory