Towards short term geodynamics

• Autorzy: Zanimonskiy Y. , Kryński J.
• Konferencja: 6th Geodetic Millenium Meeting Poland-Italy (6; 29.06-1.07.2000; Kraków, Poland)
• Języki publikacji: EN

Abstrakty

EN

Geodynamics at present associates with comparatively slow movements of the Earth crust. The tidal phenomenon with its main part being regular and predictable is not considered as a subject of classical geodynamics. However, the non-modelled variations in observed gravity may be interpreted in terms of short-term geodynamics. Supposedly the mantle-crust interaction is one of the reasons of superfluous tidal variations. High resolution of geodetic data acquisition in both space and time domain make the results of geodetic measurements increasingly attractive for geophysicists. Practical research is carried out at the Borowa Gora geodetic-geodynamic observatory located in contact zone of lithospheric plates. The residuals obtained by subtracting a tidal model from a series of gravity data were processed using the short-term spectral analysis. The resulted superfluous tidal variations consisting of periodic terms of periods from 3 up to 24 hours at a level of a few microgals could be interpreted as an indicator of non-elastic movements of the Earth crust. On the other hand the short-term time variations of the relative position of two close to each other permanent GPS stations were investigated. The magnitudes of the obtained oscillations of 12 and 24-hour periods seem to exceed the estimated errors of GPS relative positioning using 4 hour long observing sessions. The correspondence between the oscillations in gravity and GPS derived height was obtained. An attempt of modelling these oscillations was undertaken. The blocks of the crust are considered to rise and fall, rocking on the tidal wave in the body of the Earth. The gravity signal on the surface, due to the tidal motion of the mantle, is modified by the motion and deformation of the crust. Model based on a weak hysteresis in crust-mantle interaction was investigated. Modelled superfluous variations obtained at a few sites show close similarity to the observed ones in time and in frequency domain. It was shown that the information ordinarily removed from the data by averaging over daily intervals could be useful not only for geodesists but also for a wide spectrum of Earth scientists.

Słowa kluczowe

EN

GPS technology; geodynamics; scientific research

PL

badania naukowe; GPS system; geodynamika

• Wydawca: Wydział Geodezji i Kartografii Politechniki Warszawskiej
• Czasopismo: Reports on Geodesy
• Rocznik: 2000
• Tom: z. 8/54
• Strony: 47--54
• Opis fizyczny: Bibliogr. 8 poz., wykr., rys.

Twórcy

autor

Zanimonskiy Y.

autor

Kryński J.

• Institute of Metrology Kharkov Ukraine