The Harris-Galveston Subsidence District has a dedicated Science & Research Program to measure and monitor subsidence and provide the best available data to ensure effective subsidence mitigation efforts in Harris and Galveston counties. This program utilizes several scientific methods, technologies, and techniques, including satellite remote sensing. Interferometric Synthetic Aperture Radar (InSAR) is a remote sensing technique that uses satellites to measure land surface movement by comparing radar images collected at different time periods, with higher spatial resolution than other satellite technologies.
HGSD’s Science & Research Program is proud to share a new interactive map that provides a more comprehensive view of subsidence in our region by combining InSAR technology and Global Positioning System (GPS) data.
- The InSAR data is used to visualize changes in land surface over time to see whether the surface is moving toward the satellite (uplift) or away from the satellite (subsidence).
- The GPS station data is used to determine the station’s position on the ground and provides accurate measurements of localized changes; you can click on each GPS station on the map to view specific data for that station, including the years of monitoring and the total amount of subsidence recorded.