Monitoring and Analysis of Surface Deformation and Glacier Motion Along the Sichuan–Tibet Railway: A Case Study of the Lhasa–Nyingchi Railway Section

Abstract

The Sichuan–Tibet Railway which stretches as far as 1600 km starts from Chengdu in Sichuan Province and west to Lhasa in the Tibet Autonomous Region. The terrain along the railway is undulating, the ecological environment is fragile, and the railway passes through high-intensity active seismic belts and geological fault zones, facing a variety of geological disaster risks. Keeping abreast of changes in surface morphology along the railway and further monitoring and early warning of disasters can provide important technical support for the smooth construction and safe operation of the Sichuan–Tibet Railway. Taking the Lhasa to Nyingchi Railway section as an example, using the spaceborne SAR data, the surface deformation information along the railway was extracted by using the interferometry point target analysis (IPTA) technology, and the glacier motion information was derived by using the pixel offset-tracking (POT) technology. The observation results showed that the annual subsidence velocity was small in most areas of our study area, except the local areas along the LinMao Highway, whose subsidence velocity was more than 3.5 cm/year, which can be served as a key monitoring area. Another observation was that the velocity of glacier motion had a great relationship with the temperature change in our study area. As a whole, the velocity of glacier motion increases with the increase of temperature, and the glacier motion velocity in summer is significantly higher than that in winter. In addition, local topographic conditions such as slope and aspect also had a great influence on the glacier motion velocity of the glacier. Therefore, it is necessary to analyze the glacier motion in combination with local topographic.