Primed For Disaster? An Intimate Look At Cracks And Fissures On Larsen C Ice Shelf
It's not unusual for ice shelves to calve — or in layman's term, "split" — and collapse. In fact, scientists have seen this happen to major ice shelves in recent decades. There's Prince Gustav Channel, Larsen Inlet, Wordie, Muller, Jones Channel, and Wilkins.
However, it usually took months to years for cracks to slowly form and be visibly seen on the icy surface. But this is not the case for the Larsen C Ice Shelf found in the northwest part of the Weddell Sea and extending along the east coast of Antarctic Peninsula.
Scientists have noted rapid disintegration on one of the largest ice shelves on the continent at the speed of about 1 meter per day. Here's a closer look at how Larsen C's crack has developed over time.
August 2016: Crack Gone Deeper
The first threatening crack on the Larsen C Ice Shelf was spotted back in August 2016.
Project Midas, which is a group of UK-based Antarctic researchers investigating the effects of a warming climate on the Larsen C Ice Shelf in West Antarctica and has been closely monitoring the rift peninsula for almost two years, said it measured 22 kilometers longer compared to the last satellite images taken in March of the same year.
According to them, the rift has grown ominously fast during the austral winter and is now threatening the stability of the Larsen Ice Shelves.
January 2017: Primed To Calve
At the start of 2017, the long-running rift on Larsen C became worse, with barely 20 kilometers of ice keeping the 5,000-square-kilometer piece, roughly the size of Norfolk, from breaking away.
"If it doesn't go in the next few months, I'll be amazed," project leader Prof. Adrian Luckman, from Swansea University, told BBC News.
"There hasn't been enough cloud-free Landsat images but we've managed to combine a pair of ESA Sentinel-1 radar images to notice this extension, and it's so close to calving that I think it's inevitable," he continued.
If the ice shelves calve, Professor Luckman said Larsen Ice Shelf C will lose more than 10 percent of its area to leave the ice front at its most retreated position ever recorded, ultimately changing the landscape of the Antarctic Peninsula.
February 2017: Suture Zone
After a month, a video footage captured by the British Antarctic Survey (BAS) showed that the crack in Larsen C growing deeper and longer. It has entered a so-called suture zone, which means it has softer, wetter ice.
May 2017: Rift Suddenly Forked
The latest satellite images of the 180-kilometer-long fissure that threatens to rip apart Larsen C Ice Shelf suddenly branched out to a different direction. Currently, the 10-kilometer fork doesn't increase the rift. It has just given it a two-pronged tip.
"I think what all this means is that the gradual and persistent opening of the rift has put a lot of strain on to this ice," Professor Luckman explained.
"But because the rift tip was in this area of basically softer ice that is very difficult to fracture, then the stresses have been transferred elsewhere and something has given, i.e. it has fractured in some of the ice that is more vulnerable to breaking which happens to be about 10km further back than the current rift tip."
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