As part of the Canadian Government's main goals to ensure safe and strong communities for its citizens, the Geological Survey of Canada has recently undertaken the development of a 3-D geological model and a seamless surficial geology map of the St. Lawrence River valley in Eastern Canada. This paper summarizes the initial phase of this project, which consists of gathering, validating, and integrating existing geological and geotechnical data through a geographic information system. It presents the preliminary results towards the development of a 3-D geological model of unconsolidated sediments in the St. Lawrence Valley, based on digital elevation model, surficial geology map and subsurface information. A preliminary map of the thickness of unconsolidated sediments in the St. Lawrence Valley is presented for the first time. This map shows deeply buried bedrock zones with sediment thickness in excess of 160 m. These deep zones are critical areas with respect to regional mapping of ground susceptibility to earthquake disturbance. The potential influence of such deep zones on earthquake-induced landslides is examined. Geoscience data quality issues and problems encountered in data validating and integrating are also discussed, and potential solutions suggested.