LANDSLIDE INVESTIGATIONS IN SOUTHERN KYRGYZSTAN BASED ON A DIGITAL ELEVATION MODEL DERIVED FROM STEREOSCOPIC MOMS-2P DATA

摘要

In Kyrgyzstan (Central Asia) large landslides are widespread at the eastern rim of the Fergana Basin in an area of active mountain building (Pamir-Tien Shan). Because of the large number of landslides and their difficult accessibility in mountainous terrain the potential of GIS-based analysis of satellite remote sensing data is investigated. This goal requires a spatially and thematically consistent digital database including high resolution digital topographic data as a key element. For this purpose a Digital Elevation Model (DEM) was generated from data of the German multi-line scanner MOMS-2P (Modular Optoelectronic Multispectral Scanner). Processing steps included automated image matching for tie point generation between the 3 stereo strips, photogrammetric block adjustment for reconstructing the exterior and interior orientation of the camera, and finally DEM interpolation. Geodetic GPS measurements were carried out to determine ground control points (GCP) for photogrammetric point determination and independent check points (CP) for assessment of height accuracy of the final DEM. Height accuracy is described by mean and standard deviation of differences between GPS and DEM heights and amounts to 1.1 +/- 17.3m based on 36 CP. In a second step, orthoimages of the 4 MOMS-2P channels were derived. Both MOMS-2P stereo products were analyzed for their suitability investigating landslide phenomena in the Maili-Suu test area. GIS-based analysis including perspective visualizations, surface profiling and derivation of quantitative relief parameters led to topography-based identification of tectonically active elements as one major factor for initiating landslides. The stereo products also allowed detailed analysis of a single landslide. In case of the Kashgarta landslide spatial interference between displaced masses and surrounding stable areas was investigated incorporating geological information. These investigations showed that height accuracy and morphological detail of MOMS-2P stereo products are appropriate for regional satellite remote sensing based analysis of landslide processes in this area.