| Summary: | 碩士 === 國立高雄師範大學 === 地理學系 === 104 === There has been the issue of landslide on the western slope of Shoushan in Kaohsiung, and the sliding velocity is, on average, about 10cm a year. According to previous research, there is a large scale landslide in the above-mentioned area that contain all known small landslides based on concave-convex slope profile, hummocky topography, and a big limestone block of colluvial hillslope deposits origin embedded with many speleothem fragments. Thus, this study attempted to explore the activity and effect of the large-scale landslide in Shoushan and its effect.
This study discussed the activity of the large-scale landslide, adopting two methods below:
1.1:5000 scale maps photographed respectively in January, 1978 and October, 1996 were digitized and turned into 5mDEM. Landform changes caused by the large-scale landslide in 20 years were compared.
2.GPS static survey was used to monitor the displacement of landforms and to analyze such activities, as velocity and displacement direction, of the landslide, by comparing results. There were 11 benchmarks chosen on the basis of the facilitation to analyze the relation between the large-scale landslide and its small counterparts. From August, 2014 to November, 2015, GPS static survey had been applied for 5 times, in which, instruments were simultaneously set up in 4 benchmarks, lasting for at least 6 hours.
The results showed that there were dramatic changes from 1978 to 1996 in the uphill landslide area, and the rocks falling from the ridge and the accumulation of debris on the lower part could be the main cause. However, the change along the coast was less obvious. The landform changes implied that the large-scale landslide in the western slope of Shoushan could be two different landslides, according to both landform changes and GPS. The two landslides moved slowly in different displacement directions and at different velocities. Although most of the chosen benchmarks are in the areas with no obvious slide in the past, the results of this study demonstrated that the large-scale landslide on the western slope of Shoushan has been continuing to slide. Despite the fact that the large-scale landslide is at low velocity, further observation of its follow-up effects is suggested.
|
|---|
