Widespread and large-scale ground failures due to liquefaction occurred along the river valley of the Shiribeshi-toshibetsu River during the 1993 Hokkaido-nansei-oki Earthquake. By using the aerial photographs taken one day after the earthquake along the river, ground failures such as ground Assuring related to lateral spreading, sand boils and associated settlement were investigated, and the ground displacements both horizontal and vertical were measured by comparing the pre- to post- earthquake photographs. Horizontal displacements ranging to 1 to 3m were measured throughout the area that liquefied. The surface ground moved along a very gentle slope toward crescent lake or channel in most cases. Soil surveys were also conducted in the area where the large ground displacement occurred, which showed a fine and very loose sand deposit existing 2 to 5 m in depth below the ground surface. This paper summarizes the preliminary results of the investigation conducted so far for the above mentioned area.