Analysis of surface deformation and driving forces in Lanzhou

Surface deformation has become an important factor affecting urban development. Lanzhou is an important location in the Belt and Road Initiative, an international development policy implemented by the Chinese government. Because of rapid urbanization in Lanzhou, surface deformation occurs easily. However, the spatial-temporal characteristics of surface deformation and the interaction of driving forces behind surface deformation in Lanzhou are unclear. This paper uses small baseline subset InSAR (SBAS-InSAR) technology to obtain the spatial-temporal characteristics of surface deformation in Lanzhou based on 32 Sentinel-1A data from March 2015 to January 2017. We further employ a geographical detector (geo-detector) to analyze the driving forces (single-factor effects and multifactor interactions) of surface deformation. The results show that the central urban area of Lanzhou was stable, while there was surface deformation around Nanhuan road, Dongfanghong Square, Jiuzhou, Country Garden, Dachaiping, Yujiaping, Lanzhou North Freight Yard, and Liuquan Town. The maximum deformation rate was -26.50 mm year(-1), and the maximum rate of increase was 9.80 mm year(-1). The influence factors of surface deformation in Lanzhou was a complex superposition relationship among various influencing factors, not a result of the single factor. The interaction between the built-up area and land cover types was the most important factor behind surface deformation in Lanzhou. This paper provides the reference data and scientific foundation for disaster prevention in Lanzhou.