Characteristic Analysis of Ground Deformation in Chiba Prefecture Using Sentinel-1 Data

Ground deformation due to natural gas mining has been reported in the Chiba Prefecture. For example, in Yachimata City, the land subsided by approximately 40 cm from 1976 to 2020. In addition, reclaimed lands are found around Tokyo Bay, and periodic ground deformation monitoring is necessary. In this study, we utilized the short baseline subset (SBAS) method to determine the spatial tendency of the subsidence using Sentinel-1 to elucidate the characteristics of ground deformation in the Chiba Prefecture. The analysis was conducted using paired images of the ascending and descending orbits from January 2017 to December 2019, to determine the displacement velocity in each line-of-sight direction. Consequently, we quantitatively confirmed a large ground displacement in the Yachimata area. The estimated displacement velocity was evaluated using reference data, and the results showed that the characteristics of the variation were captured, although some residuals were observed.