Investigating land surface deformation using InSAR and GIS techniques in Cluj-Napoca city's most affected sector by urban sprawl (Romania)

Abstract

The last three decades have marked an unprecedented urban expansion of the city of Cluj-Napoca, leading to strong anthropogenic influences on the natural environment and important changes in the land-use. Due to the specific morphology of Cluj area, characterized by restrained plane surfaces, which are insufficient to support the urban expansion, more and more territories with slopes between 5°-26° are used for constructions. These areas are marked by high risks of mass movements due to their specific geological and geomorphological characteristics, therefore the present study proposes a more detailed and complex GIS and remote sensing analysis of Cluj-Napoca's most affected area by urban sprawl, in order to highlight the main changes of the city and the consequences of the human actions. One of the most used radar interferometry techniques (InSAR) was applied to detect land deformations that can threaten the infrastructure and the population. Sentinel-1B SAR imagery was processed by DInSAR methodology, resulting in a land surface deformation map, which represents an important support in generating a predisposition assessment. Based upon this evaluation, we concluded that the most predisposed neighbourhoods (from the study area) to active land deformations are the peripheral ones, as following: Dâmbul Rotund, Bună Ziua, Europa, Mănăștur, West Iris and Făget, proving that human activity and the geological setting are the main triggering factors of the discussed phenomenon.