UK researchers want to understand what triggers the Antarctic to kick out city-sized blocks of ice
British researchers hope to glean new insights into the physics of ice fracturing by studying a sector of the Antarctic that recently saw the breakaway of two mega-bergs.
The region under study is the Brunt Ice Shelf, which is the floating protrusion of glaciers that have flowed off the continent into the Weddell Sea.In 2021, the shelf produced a berg the size of Greater Paris - 1,300 sq km/810 sq miles - called A74, followed in 2023 by an even bigger block called A81 that was, at 1,500 sq km, the size of Greater London.
Researchers from the British Antarctic Survey have just returned from the Brunt Ice Shelf, where they deployed an array of instrumentation - including seismometers, radar and GPS receivers - on the remaining shelf structure.
Shelves like the Brunt are not uniform bodies but rather an amalgam of different ice types.
Some areas will be made from rock-hard glacier ice that flowed off the continent, while other areas will be sea-ice and snow that has filled gaps to act almost like a glue to hold various segments of the shelf together.
About 75% of the continent's margin has floating platforms of ice that can eject bergs.
The shedding of large segments of ice at the forward edge of a shelf is a natural behaviour.
A shelf will be in equilibrium if the ejection of bergs balances the snowfall and ice that builds the glacier from behind.
"Having a station on an ice shelf with cracks is actually helping us to do detailed studies that wouldn't otherwise be possible," he told BBC News.The BAS scientists are describing their investigations in talks at this week's European Geosciences Union General Assembly meeting in Vienna.
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