September, 2012 landslide events in Okhimath, India-an assessment of landslide consequences using very high resolution satellite data

The Okhimath area in the Uttarakhand state of India witnessed a large-scale occurrence of landslides on 14 September 2012 due to intense rainfall. As per news reports, this event resulted in the death of 51 people and a significant loss of property. In this study, the damage assessment results of the Okhimath landslides derived from the analysis of very high resolution (VHR) images received from Cartosat-2, Resourcesat-2, Kompsat-2 and GeoEye-1 satellites are presented. These datasets were acquired through a coordinated effort of the Indian Space Research Organisation and International Charter Space and Major Disasters. A total of 126 buildings, 34.5 ha of agricultural land and 7.78 km of road were identified as damaged through the VHR satellite data analysis. Using a semi-automatic landslide detection technique, 473 landslides covering a 2.25-km(2) area were also identified. Villages such as Mangali, Chunni, Brahman Kholi, Semla, Paldwadi, Saari and Giriyagaon are found to be most affected due to this event. The damage is mainly attributed to rock slides which originated in the escarpment zone which later converted to debris flows by scouring the material along the run-out zone.