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Summary of Proposal GEO1232

TitleMonitoring of landslides on east part of North Antolia Fault Zone (Kelkit Valley) using PS-InSAR method with TerraSAR-X data
Investigator Hastaoglu, Kemal Ozgur - Cumhuriyet University, Geomatics Engineering
Team Member
Master Student Postaci, Hatice Sule - Istanbul Technical University, Geomatics Engineering
Assistant Poyraz, Fatih - Cumhuriyet University, Geomatics Engineering
Phd. Abdikan, Saygın - Yildiz Technical University, Geomatics Engineering
Assistant BALIK SANLI, Fusun - Yildiz Technical University, Geomatics Engineering
SummaryMain aimof this project is determination of Landslides on Kelkit Valley by using InSAR technique. There are above seventy landslides onKelkit Valley. Landslides occure frequently in this region. These landslides cause many damages and deaths. We monitored Koyulhisar Landslide in this region by using GPS and InSAR between 2006 and 2009. We processed Envisat data between 2006 and 2009 using Stamps software PS-InSAR method.We determined similar movements both with GPS and PS-InSAR. Now we want to determinate all of landslides on East part of NAFZ by TerraSAR-X data. For this aim we are planing to monitor landslides of Kelkit Valley using Ps-InSAR technique with TerraSAR-X data between 2012 and 2015 years. For processing of TerraSAR-X data we will use STAMPS software. We are planning to purchase three period TerraSAR-X data for each year. These periods are november, april and august months. As a result we are planing to purchase 9 periods TerraSAR-X data of Kelkit Valley.If we determine any deformation on Kelkit Valley while processing first three periods using TerraSAR-X data we will start monitoring with GPS in this region to determine the direction of deformation. The Scientific and Technological Research Council of Turkey (TUBITAK)is providing financial support about 25 000 Euro for buying TerraSAR-X data and GPS campaign. At the end of this project we will prepare active landslide inventory map of Kelkit Valley and using the results of the GPS and InSAR we will test the succesful of InSAR technique with TerraSAR-X data for the determination of Landslides.
Final ReportThe main purpose of this project is to determine the existing areal deformation on the landslide areas by using modern and spatial PS-InSAR method. According to this purpose, Koyulhisar landslide region has been selected as the study site. In this study the dataset of SAR images acquired by the TerraSAR-X satellites was collected from DLR (German Aerospace Center). TerraSAR-X SAR images have been evaluated with STAMPS software. Thus, slip surfaces of the landslide region in the direction of the line of sight (LOS) was obtained by PS-InSAR method. The annual velocity values at the LOS direction were obtained for PS points by PS process. Later, interpolation maps were produced for the landslide site by using these velocity values obtained.An upheaval is observed on the southern slopes of Saytepe, that is, the city center, while a subsidence area is seen on the old landslide mass in the north of Saytepe in Terrasar-X results. Stripmap and High Resolution produce results with a correlation by 90%. Landslides occupy an important part of natural disasters. Landslides, particularly occurring near settlement areas, cause loss of life and property. Therefore, monitoring landslide movements is very important. InSAR method has been frequently used in monitoring landslides in the last 20 years as well (Fruneau et al. 1996; Singhroy et al. 1998; Rott et al. 1999; Crosetto et al. 2005; Motagh et al. 2013). The PS (Permanent Scatterers) approach is based on a few basic observations. There are ground targets that maintain a coherent reflectivity to the radar in time even when observed from different looking angles (the PS). The interferometric phase in correspondence of these targets is not randomized by temporal and geometric decorrelation phenomena (Pratti et al. 2010). Decorrelation is caused by contributions from all scatterers within a resolution cell summing differently, due to relative movement of the scatterers and/or a change in the looking direction of the radar platform. “If, however, one scatterer returns significantly more energy than other scatterers within the cell, the decorrelation phase is much reduced. This is the principle behind a ‘persistent scatterer’ (PS) pixel, also referred to as a ‘permanent scatterer’”(Hooper et al. 2012). Koyulhisar County is at a 180 km distance from Sivas and surrounded by Resadiye, Tokat in the West, Mesudiye, Ordu in the north, Susehri in the east and Zara and Hafik in the south Because the study area is within the Northern Anatolian Fault Zone (NAFZ), which is tectonically an active fault, the rocks in the region are generally faulted and cataclastic and contains discontinuities. Many old and new landslides take place in the region also depending on the high-slope topography in the region. Movement directions of these landslides generally threaten the settlement areas (Sendir and Yýlmaz 2001). Koyulhisar is a region on the NAFZ, where there are high mountains and dense forrests. It is known that this region is often exposed to landslides. Slides are observed as debris flow mostly in the north of Koyulhisar generally after an intense winter. Both of the landslides that occurred in 1998 and 2000 in the region generally happened after the most intense winter and spring of the recent years . (Sendir and Yýlmaz, 2001). In this study the dataset of SAR images acquired by the TerraSAR-X satellites was collected from DLR (German Aerospace Center). For the PSI analyses two different frame SLC TerraSAR-X (Stripmap (130 frame) and High resolution (54 frame)) images were used. One of them was chosen as master and interferograms were calculated from this master image. These interferograms are shown in Figure 1. Figure 1. Perpendicular baselines relative to master image of TerraSAR-X dataset In this study SAR images are gathered in SLC images interferogram processing is applied with the public domain Delft Object-Oriented Radar Interferometric Software (DORIS). Interferograms are produced by using Delft precise orbits. The topographic effect is reduced by an external DEM as 3’’ arc SRTM data 30 which has ~ 90 X 90 m resolution. Geocoding is referred with World Geodetic System 1984 (WGS84) reference system. In this study Stanford Method for Persistent Scatterers (StaMPS) approach was applied for the monitoring of Koyulhisar landslide. The annual velocity values at the LOS direction were obtained for PS points given in Figure 2 by PS process. Later, interpolation maps were produced for the landslide site by using these velocity values obtained . When Figure 2 is reviewed, an upheaval is observed on the southern slopes of Saytepe, that is, the city center, while a subsidence area is seen on the old landslide mass in the north of Saytepe in Terrasar-X results. Stripmap and High Resolution produce results with a correlation by 90%. Figure 2. PS points and velocity values of these points as a result of the assessment of the TerraSAR-X images a. the frame number 54 TerraSAR-X High resolution. b. the frame number 130 TerraSAR-X Stripmap. After the observation and measurements performed within the scope of the project, small and/or big movements were generally observed roughly in N-S direction. When an assessment was made considering the subsidence and/or upheaval values within the general evaluation of the study area, they were found compatible with the general landslide mechanism foreseen by the researchers, especially Sendir and Yýlmaz (2001). the scope of this study that the PSInSAR method was successful especially in the determination of regional deformation. The main cause of this success is the PS points’ representation of the whole study area in the areal sense. ACKNOWLEDGEMENTS Interferometric data were processed using the public domain SAR processor DORIS, StaMPS and satellite orbits used are from Delft University of Technology. The author grateful to The German Aerospace Center (DLR) for providing TerraSAR-X data under GEO1232. References Crosetto, M., Crýppa, B., Býescas, E., 2005. Early detection and in-depth analysis of deformation phenomena by radar interferometry. Eng.Geol. 79 (1–2), 81–91. Fruneau, B., Achache, J., Delacourt, C. 1996, Observation and modelling of theSaint-Etienne-de-Tinee landslide using SAR interferometry. Tectonophysics 265(3–4), 181–190. Motagh, M., Wetzel, H.U., Roessner, S., Kaufmann, H., 2013, ATerraSAR-X InSAR study of landslides in southern Kyrgyzstan.Cent. Asia Remote Sensing Lett. 4 (7), 657–666. Sendir, H. and Yilmaz, I., 2001 , Structural, geomorphological and geomechanical aspects of the Koyulhisar landslides in the North Anatolian Fault Zone (Sivas-Turkey)., Environmental Geology, 42 (1), 52-60. Singhroy V, Mattar KE, Gray AL. 1998. Landslide characteristics in Canada using interferometric SAR and combined SAR and TM images. Adv Space Res. 21:465-476.

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