HALLOWEEN CRACK - INTERNATIONAL
News: What is Halloween Crack?
What's in the news?
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A large
iceberg named A-83 measuring 375 square kilometres, broke off from Antarctica’s Brunt Ice Shelf last week.
Key takeaways:
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As per the European
Space Agency, this was the region’s third significant iceberg calving in
the past four years.
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Iceberg A-83 was first spotted off the Brunt Ice
Shelf in the eastern Weddell Sea. It broke from a rift known as the “Halloween
Crack”.
Halloween Crack:
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First spotted on 31 October 2016, the Halloween
Crack runs from an area known as McDonald
Ice Rumples – which is where the underside of the floating ice sheet is
grounded on the shallow seabed. This pinning point slows the flow of ice and
fractures the ice surface.
Location and Formation:
McDonald Ice Rumples:
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The crack originates in this area, where the floating ice sheet's underside is grounded
on the shallow seabed.
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This grounding point, known as a pinning point, slows the ice flow and
creates fractures on the surface.
Geological Impact:
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The McDonald Ice Rumples are caused by an
underwater obstruction where the bedrock rises into the underside of the ice
shelf.
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This results in pressure waves, crevasses, and rifts forming on the ice surface.
Characteristics of the
Halloween Crack:
Current Status:
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The Halloween Crack is presently stable.
Location:
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It runs adjacent to the more vulnerable tip of the Brunt Ice Shelf.
Potential Break-off:
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The precarious tip of the ice shelf is tenuously
held by a narrow ice strip about 600 meters long.
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If this narrow strip fails, it could lead to the
formation of a massive iceberg.
Potential Impact:
Iceberg Formation:
●
If the ice shelf's vulnerable tip gives way, it is
anticipated to generate an iceberg roughly 1750 square kilometers in size.
● This situation illustrates the dynamic and fragile nature of ice shelves in Antarctica, highlighting the complex interplay between geological formations and ice flow dynamics.