*2.4. Image Processing*

All images were pre-processed in the Sentinel Application Platform (SNAP versions 6.0 and 7.0, European Space Agency). The sequential pre-processing of the Sentinel-1 imagery was as follows: subsetting a region around the target area, applying the latest orbit file to correct for the satellite path, thermal noise removal, calibration to β0 and σ0 in a natural scale, range Doppler terrain correction using the Shuttle Radar Topography Mission (SRTM, [74]) digital elevation model (DEM) with 30 m resolution. These pre-processing steps were performed in the same sequence as in Song et al. [62], with the addition of the thermal noise removal step that was also performed by Van Tricht et al. [44]. The speckle filtering operation was avoided; therefore, the spatial resolution was retained [75–77].
