Abstract
Ainuma landslide area is located in the southwestern parts of Hokkaido where landslides have been frequently occurred.
Many depressions and upheavals exist in Ainuma landslide evidences. Specially interesting features of the Ainuma landslide are the slow speed and the long continuation.
The ground water is one of the most important factors which affect the speed and the continuation of the landslide. From the study of the water balance of small ponds which presumably originated from the preceding landslides, it is found that the flow pattern of the ground water shows concentration into the depressions. Occasionally such ground water flow triggers the next landslide.
