http://www.digitaljournal.com/tech-and-science/science/multiple-icebergs-ready-to-break-off-larsen-c-ice-shelf/article/497177

Multiple icebergs ready to break off Larsen C Ice Shelf

Posted Jul 8, 2017 by Karen Graham
As of Friday, July 7, the Larsen C Ice Shelf is showing very clear signs is it about to calve, according to the latest report from Project Midas scientists. Just three miles stand between the fast-growing crack and the open water.
Iceberg in Antarctic sea ice.
Iceberg in Antarctic sea ice.
Caitlin Gionfriddo, University of Melbourne
Readers may remember that on June 29, Digital Journal reported that Project Midas scientists reported on imagery from the European Space Agency’s Sentinel-1 satellite that showed the growth of the rift had tripled in speed between June 27 and June 28.
In another sign that the iceberg calving is imminent, the soon-to-be-iceberg part of Larsen C ice shelf has tripled in speed to more than 10 meters per day between 24th and 27th June 2017,” the scientists wrote on their Project MIDAS site.
“The iceberg remains attached to the ice shelf, but its outer end is moving at the highest speed ever recorded on this ice shelf.”
Comparison of speeds between Sentinel-1 image mosaics in early and late June 2017. The early mosaic ...
Comparison of speeds between Sentinel-1 image mosaics in early and late June 2017. The early mosaic combines displacements on the inner shelf measured between 6th and 12th June with similar ones on the outer shelf measured between 3rd and 15th June. The recent mosaic combines inner shelf displacements up to 24th June with outer shelf displacements only 3 days later highlighting a significant acceleration over those three days.
Project Midas
Build-up of stresses has caused something new
It is that increased speed of the movement of the outer edge of the attached iceberg that is newsworthy now. The increased stress being added to the iceberg-to-be as it nears its inevitable conclusion has caused the huge crack to begin cracking up.
Using images and data from ESA’s Sentinel-1 satellites received on July 6, multiple cracks were revealed in the rift tips, now within 5.0 kilometers (3.1 miles) of the ice edge.
The report reads: "We expect that these rifts will lead to the formation of several smaller icebergs, as well as the large iceberg which we estimate will have an area of 5,800 square kilometers (2,238 square miles). Or, you could look at it this way - That would be a trillion ton iceberg, estimates Live Science.
Detail of the branching occurring between 24th June and 6th July 2017.
Detail of the branching occurring between 24th June and 6th July 2017.
Project Midas
The ESA's Copernicus Sentinel-1 radar pair also carries a radar altimeter that will measure the height of the iceberg when it breaks off the Larsen C Ice Shelf. The information gathered will be useful in showing us how the Earth's land and sea ice is changing, as well as how the total volume of the planet's ice is being affected by climate change.
“Using information from CryoSat, we have mapped the elevation of the ice above the ocean and worked out that the eventual iceberg will be about 190 meters (623 feet) thick and contain about 1,155 cubic kilometers (277 cubic miles) of ice,” said Noel Gourmelen from the University of Edinburgh in the UK, according to India.com.
Iceberg could pose a threat to ocean navigation
Remember how scientists say the bulk of an iceberg is below the surface? Well, it is estimated that the iceberg will go down to a depth of 210 meters (689 feet) below sea level. This information is also important so that the iceberg can be monitored as it floats around the ocean, carried by the currents.
The iceberg suspected of sinking the RMS Titanic; a smudge of red paint much like the Titanic s red ...
The iceberg suspected of sinking the RMS Titanic; a smudge of red paint much like the Titanic's red hull stripe was seen near its base at the waterline.
The chief steward of the liner Prinz Adalbert
In 2015, the Brunt Ice Shelf calved an iceberg of similar size to the soon-to-be Larsen C iceberg. “Measurements from CryoSat showed that the Brunt iceberg was around 390 meters, so too thick to come close to ‘shore’ since the sea is shallow here,” said Anna Hogg from the University of Leeds in the UK.
“As for this new Larsen C iceberg, we are not sure what will happen. It could, in fact, even calve in pieces or break up shortly after,” Hogg said, adding, “Whole or in pieces, ocean currents could drag it north, even as far as the Falkland Islands. If so it could pose a hazard for ships in the Drake Passage."