The rifts were spotted by the Copernicus Sentinel-1 and Sentinel-2 satellites, which are part of the European Union’s Earth observation program, managed by the European Commission and the European Space Agency (ESA).
In a statement to Phys.org, Mark Drinkwater, the head of ESA’s Earth and Mission Sciences Division, said, “These new rifts appeared very soon after last year's major calving of iceberg B46. Sentinel-1 winter monitoring of their progressive extension signals that a new iceberg of similar proportions will soon be calved.”
— Erwan Rivault (@ErwanRivault) October 19, 2019
Calving refers to the process by which glaciers shed huge blocks of ice. Iceberg B-46, with an area of around 225 square kilometers, broke off from the Pine Island Glacier in 2019.
"Long-term measurements of West Antarctic Ice Sheet glaciers such as Pine Island are critical to understanding changes to the rate of loss of ice mass into the ocean, and thus Copernicus Sentinel-1 has become fundamental to gauging Antarctica's contribution to rising sea levels,” Drinkwater is quoted as saying by Phys.org.
According to a Friday blog post by the ESA, the Pine Island Glacier’s ice velocity has increased “dramatically” to more than 10 meters a day since the early 1990s, while its floating ice front, with an average thickness of about 500 meters, “has experienced a series of calving events over the past 30 years.” Some of these calving events have changed the ice front’s shape.
As calving events increase in frequency, the glacier will continue to lose mass, especially as “warm ocean currents erode the underside of the floating ice shelf,” according to the ESA.