Cracking Antarctica’s iceberg code

What RIFT-TIP does

We are studying how cracks grow in Antarctic ice shelves and how this leads to iceberg calving. Research focuses on the Brunt Ice Shelf, where rifts such as Chasm-1 and Halloween Crack have developed with two huge icebergs (A-74 and A-81) calving from the ice shelf over the last few years.

The Brunt Ice Shelf is home to British Antarctic Survey’s Halley Research Station – which was re-located in 2017 to avoid the cracks that led to the iceberg calvings.

RIFT-TIP combines field data, lab testing and computer modelling to understand what controls the ice just before it fractures and breaks. The work will improve predictions of when and how icebergs break away.

Why this matters

Iceberg calving is the main way ice shelves lose their mass. It is a natural phenomenon, but as Antarctica responds to climate change more icebergs could calve. This could allow more glaciers to flow into the sea, contributing to sea level rise.

Better knowledge of fracture growth in the ice also helps assess risks to polar research stations, infrastructure and ecosystems.

How the project works

RIFT-TIP uses several approaches to study ice fracture:

• Field monitoring: Radar, ApRES, GPS and seismic instruments track crack growth on the Brunt Ice Shelf.
• Ice cores: Shallow cores are drilled and tested in Cambridge labs to measure properties such as fracture toughness.
• Satellite data: Imagery provides context for recent rift activity and iceberg calving events.
• Fracture modelling: computer simulations to predict where and when icebergs will break off. 

Science objectives

The project aims to:

• measure how cracks grow and interact in ice shelves
• identify how ice properties affect fracture toughness
• combine field, satellite, and lab data to study calving
• develop models to predict iceberg production
• assess impacts on ice shelf stability and sea level rise

Who is involved

RIFT-TIP is a Natural Environment Research Council funded project.

It brings together glaciologists and geophysicists.

Fieldwork takes place near Halley Research Station, with laboratory testing in Cambridge.

RIFT-TIP has four objectives

1. Experimentally determine fracture toughness for two distinct ice types and define the relationships between fracture and local ice properties.
2. Model the growth of historic rifts (in particular timing) by imposing a spatial variability in fracture toughness and matching the ice shelf evolution to a dataset of ground and satellite observations spanning the last 10 years.
3. Test the ability of a phase-field fracture model (KRAKEN) to simulate the energy balance and damage at a present-day rift tip under high strain using new observations of micro-seismicity associated with elastic energy release, and mapping of location of initial cracks in un-fractured ice.
4. Predict the evolution of future rifts in a viscoelastic stress regime, using a complete dataset of ice properties, strain and initial crack distribution.

The objectives form a clear pathway to predicting the temporal evolution of large fractures in ice, not previously possible.

The work is designed to bridge the gap between small-scale laboratory observations, and regional-scale ice dynamics.

1. 70 years on the ice: the extraordinary story of Halley Research Station

   Six thousand miles from home, on a shelf of ice that moves, cracks and occasionally breaks away, British scientists have been keeping watch for seventy years.

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3. BLOG: Looking into the world’s most studied ice shelf

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1. New study provides clues to predicting iceberg calving

   A new study on Antarctica’s Brunt Ice Shelf has revealed that surface melting and seawater infiltration can have dramatically different effects on the structural strength of floating ice shelves.

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2. Scientists one step closer to predicting iceberg calving

   Scientists are a step closer to being able to predict when large icebergs will calve in Antarctica. 

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3. Team embarks on mission to investigate iceberg calving

   A team of scientists from the British Antarctic Survey (BAS) is gearing up for an expedition to the Brunt Ice Shelf in Antarctica to unravel the mysteries behind the calving processes that result in the formation of colossal icebergs.

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4. 2023-2024 field season begins for British Antarctic Survey

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1. Halley VI Research Station

   Halley Research Station is globally significant for observing the Earth, its atmosphere, and space weather.

   Read more of: Halley VI Research Station

   

2. Instrument: Phase-sensitive radar (ApRES)

   Research teams use phase-sensitive radars for determining ice shelf basal melt rates. Data is used to enhance climate models.

   Read more of: Instrument: Phase-sensitive radar (ApRES)

   

3. Ice core aquisition and analysis

   UK national facility and capability

   Read more of: Ice core aquisition and analysis