A giant iceberg can detach itself from the Brunt ice shelf in Antarctica at any time, according to reports recently released by NASA and the European Space Agency (ESA).
Monitoring the platform since 2019, using the images captured by the Copernicus Sentinel-1 mission, ESA gave the first alert in early January, informing about the possibility of an iceberg the size of the city of London could detach, which did not happen, yet. According to the agency, the data for the last 12 February indicate an “imminent” detachment.
ESA said it detected a new crack, not yet named, at the end of 2019, which has been monitored since then. It arose north of the “Halloween Crack”, detected in October 2016, and is a little further from “Chasm 1”, a gigantic crevice of more than 25 years.
Located in an area called “McDonald Ice Rumples”, Brunt’s new crack in the ice shelf grew about 2 km shortly after it was discovered, but in recent weeks it has been increasing in size rapidly, which has attention of glaciologists.
Satellite images obtained by ESA show that the most recent crack (identified in red in the image below) increased in size by about 20 km between November 18 and December 22, 2020. And the growth did not stop there: it it gained another 8 km in length towards the north on January 12th of this year.
It is not yet known what caused this rapid extension of the crack in such a short time, but University of Maryland (USA) glaciologist Christopher Shuman has an idea. “It is likely that the dynamics of the fracture near ‘McDonald Ice Rumples’ played a role, as well as in the rapid spread of ‘Halloween Crack’ in 2016,” he theorized.
He also mentions the unusual mix between mélange (combination of different types of sea ice, snow and icebergs) and blocks of ice in that area of the platform as a likely factor in accelerating crack growth.
Along with the acceleration at the edge of the ice shelf recently detected by Sentinel-1, these cracks point to a period of instability in the region, according to NASA, suggesting that the movement will lead to the formation of an iceberg or even two. Certain of detachment, what researchers do not know is when it will occur.