Many earthquakes occur along Canada's western margin near the edge of the North American Plate, but others occur within the plate in Arctic and southeastern Canada. Damaging earthquakes have occurred throughout history in both Eastern and Western Canada, and will undoubtedly recur in the future. Earthquakes have varied geological effects including ground rupture and land-level change, tsunamis, sediment liquefaction, and landslides; past earthquakes, including the prehistoric great Cascadia earthquake of AD 1700, have been studied by these effects. Historical earthquakes have caused damage to buildings and other structures, chiefly from direct shaking; future earthquakes may result in foundation failures and fires consequent on building damage. Damage can be mitigated by using earthquake-resistant designs. The Geological Survey of Canada has produced three generations of seismic hazard maps to assign hazard levels across the country; the fourth, which includes recent research developments, is nearing completion.