Potential Landslide Detection in Kelok Sembilan Flyover Using SAR Interferometry

Abstract

Kelok Sembilan flyover is located in West Sumatra-Riau province connection, Indonesia. Landslide occurs along with the connection every year. However, detecting and obtaining scientific information about the potential landslide zone in the area is difficult because it is mountainous, and there is no disaster equipment monitoring installed on it. Here, we identify the area that potential landslide using Satellite Radar SAR Synthetic Aperture Radar) technology with high accuracy until millimeter unit. Also, we showed how to observe the potential landslide with a low penetrate radar signal (C-band) and shifted polarization due to the topography in the vegetation area. The observation data is extracting from satellite Sentinel- 1A/B provided by the European Space Agency (ESA). The satellite is C-band frequency with 5.5 cm wavelength and 5 x 20-meter range-azimuth resolution. The acquisition time of SAR data is starting from October 2014 to August 2018, which is supported by 119 images. Processing the SAR data is using the Quasi-Persistent Scatterer technique to improve the number of scatterers in a non-urban area. Both ascending and descending orbit of the satellite with both VV and VH polarization were selected to confirm potential landslide detection consistency. The result of processing was validated with GPS geodetic by DGPS network configuration. Based on the QPS processing, five areas with significant land movement have been detected; one of them is collapse after ten days since the last data observation. The land movement range in the area is approximately more than 500 millimeters in four years.