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Roessner, Sigrid 
LANDSLIDE INVESTIGATIONS IN SOUTHERN KYRGYZSTAN BASED ON A DIGITAL ELEVATION 
MODEL DERIVED FROM STEREOSCOPIC MOMS-2P DATA 
S. Roessner, H.-U. Wetzel, H. Kaufmann 
GeoForschungsZentrum Potsdam, Section 1.5 — Remote Sensing, D-14473 Potsdam, email: roessner @ gfz-potsdam.de 
W. Kornus, M. Lehner, P. Reinartz, R. Mueller 
German Aerospace Center DLR, Remote Sensing Technology Institute, D-82234 Wessling, email: 
Wolfgang. Kornus @ dir.de 
Working Group IC-24 
KEY WORDS: Landslides, GIS, Photogrammetry, MOMS, DEM, GPS, Accuracy, Application 
ABSTRACT 
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. 
1 INTRODUCTION 
In Kyrgyzstan large landslides are widespread at the eastern rim of the Fergana Basin in the foreland of the Tien Shan 
(Fig. 1). Single events can cause mass movements of more than one million cubic meters within short periods of time. 
Every year landslides lead to extensive damage of settlements and infrastructures and to loss of human lives. Spatial 
assessment of landslide hazard is subject of collaboration between the GeoForschungsZentum (GFZ) Potsdam and the 
Ministry of Emergency and Civil Defence (MECD) in Kyrgyzstan. The goal is to develop a GIS-based approach 
incorporating satellite remote sensing data and existing geoscientific information about the present stage of landslide 
activity and the geological and physical-geographic conditions causing slope failures. 
This goal requires a spatially and thematically consistent digital database. A Digital Elevation Model (DEM) is a key 
element of such a database, since relief is an integrative expression of geomorphic and tectonic processes. Detailed 
information about topography is also required for topographic correction and thematic analysis of satellite remote 
sensing data in mountainous terrain. The northern part of the study area was covered by MOMS-2P data take in stereo 
mode D (Fig. 1) during the operation of the German MOMS-2P sensor on board the Russian MIR station. These 
MOMS data represent a unique opportunity for generating a DEM for a large part of the study area. 
This paper describes the procedure of DEM generation under the specific conditions of the study area and evaluates the 
result assessing GPS-based height accuracy. In a second step orthoimages of the 4 MOMS channels are derived. The 
suitability of these stereo products for investigating landslide phenomena is demonstrated for the Kashgarta landslide in 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 1259