Research Enabled through Eighteen Years of Geodesy Data Sharing by the UNAVCO Data Center Abstract


  • UNAVCO, the NSF and NASA-funded facility that supports and promotes Earth science by advancing high-precision techniques for the measurement of crustal deformation, has operated a Global Navigation Satellite System (GNSS) data archive since 1992. UNAVCO’s Data Policy includes immediate open access to data from continuous GNSS stations and open access after a 2-year embargo period for campaign data. Presently, the GNSS archive holds 3,500,000 files of data, taken principally at a large and growing globally-distributed set of permanent high precision GNSS stations. Each day on average 2,000 new files are archived and 33,000 files are distributed. The spatial and temporal resolution now available for GNSS data enables quantification of motions of the Earth’s crust at all scales with unprecedented detail and precision, leading to fundamental discoveries in plate boundary processes, continental deformation, earthquake processes, magmatic systems, and global and regional hydrological mass movements. The Plate Boundary Observatory (PBO) is the UNAVCO-operated 1100-station geodesy component of EarthScope that studies the three-dimensional strain field resulting from active plate boundary deformation across the western US. Processing of the entire set of data by the PBO Analysis Centers (MIT, New Mexico Tech and Central Washington U.) has added position time series to the open GNSS data products available from the UNAVCO Data Center. This data set forms the basis for an overarching analysis of various non-tectonic processes, such as the effect of soil moisture on multi-path. With the ultimate goal of understanding tectonic and magmatic motions, the ability to model these signals and remove them to further elucidate the tectonic signal alone is crucial. GNSS data are also leading to global strain-rate maps with unprecedented resolution, which allow an integrated description of the surface kinematics accounting for rigid plates and plate boundary zone deformation [Kreemer et al., 2003]. An important contribution to these analyses for the Great Basin is MAGNET, a 307-station array operated by the University of Nevada with 30-50 active stations per day since 2004 [Blewitt et al., 2004]. The simultaneous increase in GNSS data and analysis expertise now allows for routine global analysis of many thousands of GNSS stations. Such analysis ensures that all phase ambiguities are fixed and that common-mode errors are significantly reduced and thereby allow for increased spatial and temporal resolution for strain-rate models and other solid-earth investigations.These examples highlight two research areas where exciting advances are built upon the GNSS data available from the UNAVCO Data Center. The continued open availability of GNSS data will provide an invaluable resource for refinement of current understanding of geodesy and completely new discoveries into the future.Blewitt, G., C. Kreemer, and W.C. Hammond (2009). Geodetic observation of contemporary deformation in the northern Walker Lane: 1. Semipermanent GPS strategy, p. 1–15, doi: 10.1130/2009.2447(03).Kreemer, C., W.E. Holt, and A.J. Haines, An integrated global model of present-day plate motions and plate boundary deformation, Geophys. J. Int., 154, 8-34, 2003.

publication date

  • 2010

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