In this work, the analysis of TerraSAR-X satellite images combining both conventional and advanced Differential Synthetic Aperture Radar Interferometry (DInSAR) approaches has proven to be effective to detect and monitor fast evolving mining subsidence on urban areas in the Upper Silesian Coal Basin (Poland). This region accounts for almost three million inhabitants where mining subsidence has produced severe damage to urban structures and infrastructures in recent years. Conventional DInSAR approach was used to generate 28 differential interferograms between 5 July 2011 and 21 June 2012 identifying 31 subsidence troughs that account up to 245 mm of displacement in 54 days (equivalent to 1660 mm/year). SqueeSAR^TM processing yielded a very dense measurement point distribution, failing to detect faster displacements than 330 mm/year, which occur within the subsidence troughs detected with conventional DInSAR. Despite this limitation, this approach was useful to delimit stable areas where mining activities are not conducted and areas affected by residual subsidence surrounding the detected subsidence troughs. These residual subsidence mining areas are located approximately 1 km away from the 31 detected subsidence troughs and account for a subsidence rate greater than 17 mm/year on average. The validation of this methodology has been performed over Bytom City were underground mining activity produced severe damages in August 2011. Conventional DInSAR permitted to successfully map subsidence troughs between July and August 2011 that coincide spatially and temporally with the evolution of underground mining excavations, as well as with the demolition of 28 buildings of Karb district. Additionally, SqueeSAR^TM displacement estimates were useful to delimit an area of 8.3 km² of Bytom city that is affected by a residual mining subsidence greater than 5 mm/year and could potentially suffer damages in the midterm. The comparison between geodetic data and SqueeSAR^TM for the common monitoring period yields and average absolute difference of 7 mm/year, which represents 14% of the average displacement rate measured by the geodetic benchmarks. These results demonstrate that the combined exploitation of high-resolution satellite SAR data through both conventional and advanced DInSAR techniques could be crucial to monitor fast evolving mining subsidence, which may severely impact highly populated mining areas such as the Upper Silesia Coal Basin (USCB).

In the last few years, several advances have been made in the use of radar images to detect, map and monitor ground deformations. DInSAR (Differential Synthetic Aperture Radar Interferometry) and A-DInSAR/PSI (Advanced DInSAR/Persistent Scatterers Interferometry) technologies have been successfully applied in the study of deformation phenomena induced by, for example, active tectonics, volcanic activity, ground water exploitation, mining, and landslides, both at local and regional scales. In this paper, the existing European Space Agency (ESA) archives (acquired as part of the FP7-DORIS project), which were collected by the ERS-1/2 and ENVISAT satellites operating in the microwave C-band, were analyzed and exploited to understand the dynamics of landslide and subsidence phenomena. In particular, this paper presents the results obtained as part of the FP7-DORIS project to demonstrate that the full exploitation of very long deformation time series (more than 15 years) can play a key role in understanding the dynamics of natural and human-induced hazards.

The paper presents the results of terrain subsidence monitoring in Poland’s Upper Silesian Coal Basin (USCB) mining area using Differential Interferometry Synthetic Aperture Radar (DInSAR) and Persistent Scatterer Interferometry (PSI). The study area accounts for almost three million inhabitants where mining which started in the 19th century, has produced severe damage to buildings and urban infrastructures in past years. The analysis aimed to combine eight different datasets, processed in two techniques, coming from various sensors and covering different periods. As a result, a map of areas that have been exposed to subsidence within 3045 square kilometers was obtained. The map covers a period of twenty years of intensive mining activities, i.e. 1992–2012. A total of 81 interferograms were used in the study. The interferograms allowed not only to determine subsidence troughs (basins) formed from 1992 to 2012 but also to observe subsidence development over time. The work also included five sets of PSI processing, covering different temporal and spatial ranges, which were used to determine zones of residual subsidence. Based on InSAR datasets, an area of 521 square kilometers under the influence of mining activities were determined. Within the subsiding zones, an area of 312.5 square kilometers of the rapid increase in subsidence was identified on the interferograms. The study of combined different InSAR datasets provided large-area and long-term information on the impact of mining activities in the Upper Silesia Coal Basin.

The article contains results obtained from realization of the Polish and Lithuanian Baltic case study within the EU – FP 7 SubCoast project, which one of the primary aims was analysis of vertical ground movements, potentially causing geohazards in the coastal areas. To reach this goal Interferometric Synthetic Aperture Radar (InSAR) data were obtained. For the Polish and Lithuanian Baltic coast ERS archive radar data were processed in order to provide Permanent Scatterer (PSInSAR, PSI) results that were then used to create the new innovative product – Dynamic DEM (DDEM). The deformation model defined by the SubCoast project normally needs to be created by merging InSAR, satellite navigation (GNSS), optical leveling and/or gravimetry measurements. Elaboration of DDEM enables more effective comparison between PS and tectonic features. Comparison of PS time series with groundwater changes shows a direct correlation, confirming impact of groundwater on subsidence or uplift of the ground surface. The results of the geological interpretation demonstrated that the examples of movements detected by PSI include subsidence linked to deformation of engineering constructions, compaction of organic or weak soils, and eolian accumulation or deflation processes of the sand dunes. For the Polish and Lithuanian coasts most of the area proved to be stable, nevertheless some local deviations up to –15 mm per year of movement were found.