Nearly Empty Fuel Barrel Sinking into Liquefied Active Layer in Till in a mudboil
These two 10-imperial-gallon barrels, each with a weight of less than 20 kg (the completely exposed barrel had been filled with aviation fuel and still had a small amount of liquid in it…it weighed perhaps an additional 6 or 7 kg), were placed side by side on a stable, lichen-covered mudboil surface and on an active, lichen-free part of the same mudboil by Dr. Tony Davidson of the Geological Survey of Canada (name stenciled on the barrels) in 1968. Over nine years, the barrel on the bare part of the mudboil sank, despite its lighter weight that produced a loading of approximately 10-20g/cm2 or less. This is another example of the effect of low liquid limits on till and fine-grained marine sediments that underlie much of their area. For other examples of this phenomenon see images 0063, 0157, 0196, 0197, 0198. For an explanation of the causes and measurements that indicate tendency of sediments that liquefy under low stress and low moisture contents, see the discussion of Atterberg limits under image 0240. The propensity for sediment in the active layer in this area of deep permafrost to liquefy whenever lightly loaded has important ramifications for construction, terrain disturbance or other human or caribou activity.
Updated 05/07/2010 AW