Coastal subsidence rate


By applying the interferometric technique (PSP-IFSAR) to radar satellite data, it is possible to measure the component of the ground displacement along the satellite’s line of sight, for a series of radiometrically stable points, called persistent scatterers (PS). The data is generated through the e-Geos processing chain. By combining the measurements obtained in two different acquisition geometries using a post-processing tool, the vertical and horizontal components are extracted to obtain the subsidence rate, while projecting the displacements measured along the direction of maximum slope of the land (with the help of a DEM) it is possible to get information on coastal landslide activities.

PSP-IFSAR acquisition geometry

Operating scenarios

  • Base knowledge
  • Ordinary monitoring

Technical specification

Spatial resolutionSensor function used Sentinel 1A IW mode: 12 mx 4 m Cosmo- SkyMed HIMAGE: 3 mx 3 m
Coverage areaSensor function used Sentinel 1A IW mode: 50 km x 50 km Cosmo- SkyMed HIMAGE: 10 km x 10 km
Geographic accuracySensor function used Sentinel 1A IW mode: 12 m Cosmo- SkyMed HIMAGE: 1.5 m
Information Age4 months
Measurement uncertaintySensor function, number of images and time period Sentinel 1A IW mode, 30 images, 2 years: 2 mm / year Cosmo- SkyMed HIMAGE, 30 images, 2 years: 4 mm / year
Measurement / projection unitmm / year geographical reference system
EO data in inputPS data obtained from satellite data processing Sentinel 1, Cosmo- SkyMed
Input data usedNA
Data used for validationNA
Algorithm methodBreakdown of motion based on observation geometry
FormatAscii files
Refresh rate4 months

Example – subsidence rate

Postprocessing tool for Vertical displacement estimation. input (left side): Displacement measurements in the two observation geometries (ascending and descending). Output (right side): estimation of motion components along with vertical and East-west directions

Example – Subsidence EW

Analysis along Bormida di Millesimo river, near Savona Italy- East-west component estimation

Example – Subsidence VERT

Analysis near Savona area Italy- Vertical component estimation