Comparing the magnitude of the earth's vertical relocation using the SBAS algorithm in X and C radar bands (Case study: Tehran lands)

The earth’s crust has not been fixed during the geological history and reshaped continually under the influence of internal and external factors. Uplifting or subsidence in some areas of the earth’s crust, especially in thin ones has been led to some changes in its surface which cause to destroy natural phenomena and human-made structures. In the present research amount of the earth’ vertical displacement in the Tehran lands using a time series analysis based on short location baseline (SBAS) and the differential radar interferometry with synthetic aperture technique (DINSAR) has been assessed. Accordingly, 19 images of the ENVISAT ASAR satellite (C band) and 11 images of the TERRA SAR satellite (X band) have been used in which the time span was 1680 and 187 days, respectively. After the image processing, maps of the earth’s surface displacement for all dates were calculated than the primary image and the map of the earth’s surface vertical displacement per day was provided for each sensor. Assessing results of two sensors indicated that, subsidence was moderately 0.761 mm and 0.777 mm per day for ASAR and TERRA SAR sensors, respectively. Results also represented that, some areas showed uplifting, in which the amount of uplifting for ASAR and TERRA SAR sensors were 0.529 and 0.476 per day, respectively. Generally, considering that the date and wavelength were different, obtained results for uplifting and subsidence areas were closed for both sensors.