Mapping ground movements in open pit mining areas using differential SAR interferometry

The coherent pixel technique is an advanced differential SAR interferometry technique that has been used for mapping and monitoring ground movements in La Union mining area (Murcia, SE Spain). This technique was originally used to monitor mining subsidence in La Unión Town but unknown ground instabilities were detected in an abandoned open pit mining area nearby. Measured displacements have been analyzed with respect to geometrical and geological factors that play a role in ground movements. Then a "blind test", consisting on geomorphological mapping of detected deformed areas, was performed in order to identify the existence of unknown active processes: slope instabilities and flat accumulation areas. Finally, a detailed analysis of these results has permitted to illustrate the advantages and disadvantages of using this technique for mapping ground movements in mining areas.