Landslide investigation using SAR Interferometry on selected regions of Idukki district, Kerala, India

Abstract

Landslide, a disturbance in the slope stability causing alteration in the slope profile can be triggered by nature or anthropogenic activities. It is important to monitor the landslide spots so that the devastating effects in resources, human life and economy can be minimized. This paper analyses landslide disasters in Devikulam taluk of Idukki district, Kerala with SAR (Synthetic Aperture Radar) Interferometry technique considering the torrential rainfall of 2018 (June - August) using Sentinel-1 C band (5.36 GHz) SAR data. Fourteen ground truth landslide locations coincided with interferogram observations. On the CartoDEM derived slope, 22 slides were observed to be located in steep slope, 5 slides in moderate slope and Polinjapalam slide was located in rolling terrain. The overall accuracy of the study in preliminary detection of landslides through the interferogram was computed to be 48.72 %. The vertical displacement was quantified in the range -0.755 m to -0.008 m proving the technique is effective.