DInSAR based land deformation detection in the karst landscape of Gunung Sewu

Abstract

Hydrologic element specifically precipitation was fathomed to contribute in land deformation of karst landscape. Cempaka Tropical Cyclone (TC) had ensued in the last of 2017 in the Indian Ocean implicated to a high rate of rainfall upon the karst landscape of Gunung Sewu. This research aimed to identify the areas where sustained of land deformation due to the Cempaka TC. This research used a method of Differential Interferometry Synthetic Aperture Radar (DInSAR) by utilising a pair of Sentinel-1A satellite imageries to obtain the information of land deformation. The research result demonstrated the karst landscape of Gunung Sewu encountered land deformation after the Cempaka TC had impinged it. The land deformation occurred in the northern region of Gunung Sewu karst landscape in the forms of land uplifting with a range of 1 – 2 mm/year (115.36 km2) and gradually became a land subsidence with a range of -1 - -4 mm/year (989.25 km2) in the southern region of Gunung Sewu karst landscape. This finding was important as a preliminary research to mitigate the hazards and conserve the karst landscape of Gunung Sewu upon the threats of extreme weather in the future.