Crustal deformation studies using space geodetic and terrestrial techniques and methods

The research activities deal with crustal deformation studies over different spatial scales, from the local scale to the regional and global ones, by using mainly, however not limited to, space geodetic techniques. Starting in mid-1996, a network of five permanent GPS/GNSS stations has been installed in North-eastern Italy; they are located at Bologna, Medicina, Loiano, Marina di Ravenna and Trieste. Two of these sites, namely Bologna (BOLG) and Medicina (MSEL), belong to the European permanent GNSS network EPN (EUREF Permanent Network) and provide daily the acquired data to the EPN Central Bureau (Brussels). The site locations are such to contribute to different scientific objectives. For example, studies of tectonic nature are conducted through the analysis and interpretation of data allowing high accuracy estimates of both the vertical and horizontal motions of the Earth’s crust. Subsidence affects the Po Plain and North-eastern Italy; therefore, monitoring and studying this phenomenon is not only scientifically relevant but it has also major social-economic implications. The high-accuracy determination of crustal movements has most important applications in areas subjected to hydrocarbons upstream/production, reinjection and storage. Contributions to sea-level change/variations studies are provided by the Trieste and Marina di Ravenna stations co-located with the tide gauges; in fact, the GPS data allow estimating with high accuracy and continuity the vertical land movements that shall be removed from the tide gauge measurements. Sea level studies, which are important in the light of changing climate, include also the analysis and interpretation of tide gauge and satellite altimetry data at regional scale such as that of the Mediterranean basin.

At Medicina, since 1996, a superconducting gravimeter (SG) is operative in the framework of a collaboration with the Bundesamt fuer Kartographie und Geodaesie (BKG, Frankfurt, Germany). This instrument, co-located with the GPS (MSEL), is part of the international network of SGs (Global Geodynamics Project, an IAG Service). At the beginning of July 2019, a second GPS station (MSE2) has been installed in Medicina in collaboration with Prof Matteo Berti of BIGEA (Univ. Bologna). The two stations are founded at different depths and this will allow studies of the mechanical properties of the soil. The SG measures the temporal variations of the gravity field continuously and it is periodically controlled by means of absolute gravity measurements. Continuous monitoring of height and gravity changes allows the separation of the gravity potential signal due to mass redistribution from the geometric signal due to height changes. This comparative study provides the means for the sound interpretation of crustal deformation processes. The group is also actively contributing to the Open Air Laboratory (OAL) being developed in the framework of the EU OPERANDUM project and, in this context, a first realization was the installation of a GPS station (GORO) in October 2019 co-located with the tide gauge operative at Goro in the delta of the River Po.

Future activities will be based, however not limited to, on further developments of the researches previously described.

Funding

• ENI SpA
• EU OPERANDUM Project
• RFO University of Bologna

Collaborations

• Bundesamt fuer Kartographie und Geodaesie (BKG, Frankfurt, Germany)
• DICAM, University of Bologna, Italy
• BIGEA, University of Bologna, Italy
• ISMAR, CNR, Trieste, Italy