The redistribution of mass associated with the growth and decay of continental ice sheets gives rise to major glacial loading and unloading effects over timescales of several tens of thousands of years. The response of Earth's crust, mantle and gravitational field is referred to as glacial isostatic adjustment (GIA). For instance, during the decay of a major ice sheet, the unloading of mass results in glacial rebound of the crust, which continues well after the disappearance of the ice. This process is well known from previously glaciated regions such as Canada and the United States, Fennoscandia, the British Isles and Siberia (e.g. Ekman, 1991); areas where this process is still active today, some 10–15 ka after the last deglaciation. In previously glaciated terrain without strong tectonism, GIA is the most significant geodynamic process governing vertical deformation of the crust (e.g. Peltier, 1994).

The downwarping and rebound processes can result in reactivation of major bedrock fracture zones with related differential crustal movement. Such glacially induced fault movements in large fracture zones may cause earthquakes of large magnitude, possibly up to M8 (e.g. Stewart et al., 2000). There is evidence of glacially induced faulting events having occurred as the ice sheet retreated at several locations in northern Fennoscandia (e.g. Lagerbäck, 1979; Olesen, 1988).