Vertical land motion derived from persistent scatterer interferometry and its relationship with tectonics and coastal dynamics in the Southern Caribbean of Costa Rica

The Persistent Scatterer InSAR technique is widely used to determine vertical land movement in areas where other sources of information, such as GNSS stations, are unavailable or in areas that are difficult to access. To estimate the vertical land velocity in the Southern Caribbean of Costa Rica, a parameter required in other research (e.g., for the study of coastal dynamics), interferometric techniques were applied. The methodology involved the use of Sentinel-1 Radar images from both ascending and descending orbits. These images were preprocessed using SNAP software, and later, StaMPS software was used to estimate the line-of-sight velocity for each orbit. The Atmospheric Phase Screen effect was corrected using the linear model available in the TRAIN software. These results were then combined to estimate the vertical velocity. As a result, LOS velocities were estimated, ranging between − 1.0 mm/year and − 21.8 mm/year for the ascending orbit, and between − 12.5 mm/year and + 8.5 mm/year for the descending orbit, with a root mean square error of 1.67 mm/year and 1.21 mm/year for the ascending and descending orbits respectively. The vertical land velocity was estimated, yielding an average value of − 7.04 mm/year, which is consistent with data derived from GNSS stations. These findings, obtained through the application of geodetic techniques, indicate a subsidence process that should be considered when conducting coastal dynamics studies.