Temporal change in the sediment discharge from the gigantic landslide occurred on Mt. Bawakaraeng, Indonesia

Abstract

On March 26, 2004, the gigantic landslide occurred on the caldera wall of Mt Bawakaraeng, Indonesia. This paper quantitatively shows the temporal change in the sediment discharge from the huge amount of the deposit of the landslide through the differentiation of the multi-temporal DEMs obtained by the stereo matching of two optical satellite images. Firstly, the landslide buried the original river channel completely. In the next year, gully erosion dominated on the entire landslide deposit and some part of the gully bed was found to degrade up to 60 m. The total amount of sediment which had discharged from the area of interest was estimated to be 36. 3 million m³. In the second post-event year, such a severe and entire degradation was almost terminated and some part showed a tendency of the river bed aggradations. The total amount of the discharged sediment drastically decreased and was estimated to be 8. 3 million m³.