EARLY GEOHAZARD DETECTION IN COLD MOUNTAIN REGION BASED ON INSAR TECHNOLOGY WITH SEASON PARTITION-EXAMPLE OF EASTERN HIMALAYAN SYNTAXIS REGION

The significant seasonal changing of surface coverage makes it is difficult to maintain the InSAR interferometric coherence with a long temporal baseline in the cold mountain region. It causes a negative effect in the identification of geohazard in such region. Here, we propose a geohazard identification method based on InSAR seasonal coherence variation in the cold mountain region. First, the InSAR time series interferograms and coherence are obtained. Then, according to the InSAR coherence variation, each year is divided into summer season, transition season and winter season. Second, according to the characteristic of the coherence of the transition season interferometric pairs, they can be added into summer season or winter season groups. Then, the time series InSAR deformation in summer season and winter season are extracted based on Stacking-InSAR technique, respectively. It is noted that some long temporal baseline InSAR interferometric pairs with a high coherence also are introduced into InSAR time series analysis. Finally, the Stacking-InSAR deformation in summer season and winter season are jointly used to detect the geohazard in the cold mountain region. In this study, the Eastern Himalayan Syntaxis is set as study area, and the proposed method is adopted to detect the geohazard in this area. And it is found that only 16% geohazards can be identified by both the summer and winter InSAR results, which indicates that different geohazards in summer and winter. In addition, the proposed method detects more 28% geohazards than the result of traditional Stacking-InSAR technology using all interferograms. Therefore, the proposed method can accurately and effectively detect geohazard in the cold mountain region. It can provide a help to the reduction and prevention of geohazard in such region.