ABSTRACT
A huge creep type landslide has been identified near the Saga city of Japan in 1999. It has been evidenced that this landslide was activating for several years since the quarry is opened up at the bottom of the valley. This landslide was monitored for nearly two years since noticing the tensional cracks on the upper reaches, followed by the progressive moving down the slope. Several survey points were located throughout the landslide mass and they were continuously monitored in frequent intervals for the horizontal as well as vertical movements.
Analysis of the data from the surveying revealed the directions and the magnitude of movements varying through out the sliding mass. 3-D analysis of those displacement data could be effectively utilized in determining the geometry of the slide surface including the depth and shape. The information obtained on the slip surface was well correlated with the results of the geological and structural study and the borehole drilled within the landslide. The results were further clarified by the pipe strain gauge installed subsequently within the moving mass.
