Polar Seminar: Till Wagner "The ‘footloose’ mechanism: iceberg decay from hydrostatic stresses"


 
05/13/2014 - 2:00pm

We propose a mechanism of iceberg breakup that may act together with the recognized melt and wave-induced decay processes. Our proposal is based on observations from a recent field experiment on a large ice island in Baffin Bay, East Canada. We observed that successive collapses of the over- burden from above an unsupported wavecut at the iceberg waterline created a submerged foot fringing the berg. We suggest that the buoyancy stresses within the berg induced by such a foot may be sufficient to cause moderate-sized bergs to break off from the main berg. A simple mathematical model is developed to test the feasibility of this mechanism. The model suggests that once the foot reaches a critical length, the induced stresses will be sufficient to cause breakup. The theoretically predicted maximum stable foot length is found to compare well to the data on breakup that was collected in situ. Further, the model provides analytical expressions for the ‘rampart-moat’ iceberg surface profiles that had been observed previously. 

Event Contact: 
Matthew Siegfried
Event Calendar: 
Location: 
303 Munk