This work provides a detailed description of an operational service based on the processing of Sentinel-1 satellite SAR (Synthetic Aperture Radar) data aimed at monitoring the ground surface displacements in the Sauro valley, southern Italy, where oil production activities are in progress. The operational character of the service is ensured by (i) the maturity of the SAR data processing methodology used, which is based on Multi Temporal Interferometry (MTInSAR), and (ii) the availability of the Sentinel-1 SAR images acquired in a systematic way (1 image every 6 days) over the area of study.
The procedures and tools here presented are of general applicability and can be used in other geographic regions. Furthermore, the proposed approach allows the integration of in-situ data based on GNSS measurements and on the use of corner reflectors thus enabling also the cross-validation of the ground surface displacement maps produced by the service. In particular, the complementary data from GNSS permanent stations installed at corner reflector sites demonstrated a very good agreement between GNSS and SAR measurements. This confirms the high potential of SAR interferometry in providing reliable wide-area displacement maps. More specifically, the application of these tools and procedures to the Tempa Rossa oilfield in the Sauro valley, Basilicata, allowed to deploy a modern and efficient monitoring process, complying with the Guidelines For Monitoring Seismicity, Ground Deformation And Pore Pressure In Subsurface Industrial Activities which recommend, among other things, the use of satellite methods to detect ground deformations using interferometric technologies with an accuracy of some millimeters/year.
The objectives of a monitoring system are often manifold. In industrial projects, such as Tempa Rossa oil field, an efficient monitoring system is not just a matter of regulatory compliance and of fulfilling requirements [MISE, 2014], but it also increases the overall safety of the project.
Space-based Multi Temporal SAR Interferometry (MTInSAR) has been developed in late 1990s - early 2000s and its potential has been demonstrated for both mapping and monitoring the movements of natural and anthropogenic features [Wasowski, 2018]. The technique has reached a high maturity level and robustness, as well as a millimeter accuracy in the measurements of ground surface displacements.