The RING GPS network: a research geodetic infrastructure to study plate boundary deformation in the Central Mediterranean

摘要

We present the INGV (Italian National Institute of Geophysics and Volcanology) geodetic research infrastructureand related facilities, dedicated to the observation and monitoring of current deformation of the plate boundarybetween Africa and Eurasia. The recent increase of continuous GPS (CGPS) stations in the Central Mediterraneanplate boundary zone offers the opportunity to study in detail the present-day kinematics of this actively deformingregion. For answering all the open questions related to this complex area, INGV deployed a permanent, integratedand real-time monitoring CGPS network (RING) all over Italy. The RING network (http:/ring.gm.ingv.it) is nowconstituted by more than 150 stations. All stations have high quality GPS monuments and most of them areco-located with broadband or very broadband seismometers and strong motion sensors. The RING CGPS sitesacquire at 1Hz and 30s sampling rates (some of them acquire at 10 Hz) and are connected in real-time to theINGV acquisition centers located in Roma and Grottaminarda. Real-time GPS data are transmitted using differentsystems, such as satellite systems, Internet, GPRS/UMTS and wireless networks. The differentiation of datatransmission type and the integration with seismic instruments makes this network one of the most innovativeCGPS networks in Europe. Furthermore, the INGV data acquisition centers acquire, archive and analyze mostof the Italian CGPS stations managed by regional or national data providers (such as local Authorities andnation-wide industries), integrating more than 350 stations of the CGPS scientific and commercial networksexisting in the Italian region. To manage data acquisition, storage, distribution and access we developed dedicatedfacilities including new softwares for data acquisition and a web-based collaborative environment for managementof data and metadata. The GPS analysis is carried out with the three main geodetic-quality softwares used in theGPS scientific community: Bernese GAMIT an GIPSY-OASIS. The resulting daily solutions are aligned to theITRF2005 reference frame. Stable plate reference frames are realized by minimizing the horizontal velocities atsites on the Eurasia and Nubia plates, respectively. The different software-related solutions consistency RMS iswithin 0.3 mm/yr (Avallone et al., 2010). The solutions are then evaluated with regard to the numerous scientificmotivations behind this presentation, ranging from the definition of strain distribution and microplate kinematicswithin the plate boundary, to the evaluation of tectonic strain accumulation on active faults. The RING networkis strongly contributing to the definition of GPS velocity field in the Italian region, and now is able to furnisha newly and up to date view of this actively deforming part of the Nubia-Eurasia plate boundary. INGV is nowaiming to make the RING (and integrated CGPS networks) data and related products publicly available for thescientific community. We believe that our network represents an important reality in the framework of the EPOSinfrastructure and we strongly support the idea of an European research approach to data sharing among thescientific community. We will present (a) the current CGPS site distribution, (b) the technological description ofthe data acquisition, storage and distribution at INGV centers, (c) the results of CGPS data analysis, and (d) theplanned data access for the scientific community.