Ice scour is a poorly understood phenomenon which occurs when ice (pressure ridge or lceberg) moves while in contact with the seabed. It is of economic significance due to the like hood of disruption of seabed structures. Current debate centres over the failure mechanisms associated with scour and the consequent subseabed deformations. Phenomenological studies of lceberg scouring by C-CORE have provided the framework for more quantitative analyses where in the stress and displacement fields below scouring icebergs have been investigated. These studies include excavation of relict ice scours in western Canada where well preserved iceberg scour features from glacial Lake Agassiz have been found. These studies have provided confirmation of subscour deformations associated with scouring, and have lndicated a failure mechanism. In addition, observations have been made of ice scour tracks for relatively small "icebergs" (ice pans from the spring breakup) ranging up to approximately 50 tonnes in size, across the St. Lawrence tidal flats near Montmagny, Quebec. The observations have led to the experimental modeling of iceberg processes in the laboratory in order to determine the stress and displacement fields below a scouring iceberg.
Ice scouring of the seabed is a ubiquitous feature of most of the coastal regions of northern continents. Figure 1 shows areas in the northern hemisphere where ice scoured features have been documented in the literature and also those areas where extensive ice scour could be expected based on known present and past ice condltl0ns. Ice scour occurs when ice impacts the seabed. In open waters, such as the east coast of Canada as far south as the southern tip of the Grand Banks, (and sometimes beyond) and ln the northern Norwegian Sea, ice scour is normally associated with glacial ice in the form of icebergs.