Integration of Distributed Dense Polish GNSS Data for Monitoring the Low Deformation Rates of Earth's Crust.

This research concerns the possibility of monitoring low deformation rates in tectonically stable regions using GPS/GNSS observations. The study was conducted in an area of Poland located in Central and Eastern Europe, where horizontal stress resulting from plate boundary forces in the N–S or NNE–SSW direction has been observed. This stress can translate into deformation of the Earth's surface. The problem, however, is that it corresponds to strain rate magnitudes of much lower than 10 × 10⁻⁹ per year. This is not much higher than the figure determined using current GNSS observation capabilities. In this study, long-term observations from several GNSS networks were used. The result was a very dense but irregular velocity field. By carefully analyzing and filtering the data, it was possible to eliminate the impact of various errors, creating a more consistent velocity field. This article presents a final GNSS strain rate model for Poland and determines the impacts of the analysis methods on its variation. Regardless of the filtering method adopted, dominant compression rates in the N-S direction are evident. Moreover, this result is consistent despite the use of varying velocity. This shows that even in tectonically stable regions, strain rates can be monitored at 10⁻⁹ per year (below 3 × 10⁻⁹/year). [ABSTRACT FROM AUTHOR]