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The assessment of the results achieved in our division at the field of physical geodesy is summarised. The studies at the fields of Earth rotation, Earth tides, Earth gravity and the global and regional Earth deformations related to geodesy and geodynamics are presented by citation of the most important publications and dissertations, which cover the history of our institute. The paper ends with the case study related to the newly developed full roving GPS observation strategy.

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Acta Geodaetica et Geophysica Hungarica
Authors:
P. Varga
,
Z. Bus
,
B. Süle
,
A. Schreider
,
C. Bizouard
,
D. Gambis
, and
C. Denis

In its first part this work focuses on connection of length of day (LOD) with centered and eccentric geomagnetic dipole fields described with the use of Gaussian coefficients derived from global geomagnetic observations is discussed for the epoch 1900–2000. The statistical comparison of temporal variation of earth magnetic and astronomical data shows close correlation of geomagnetic dipole momentum M 0 and ΔLOD. It should be mentioned that the time-correlation is closer when the centred geomagnetic dipole is used for statistical modelling. In the same time no relation was found between ΔLOD and the orientation variations of the geomagnetic dipole.In the second part of present study the connection of geomagnetic field and the LOD is investigated in geological time-scale. A significant ΔLOD was found which coincides in time with the geomagnetic Mesozoic low. The reason of this coincidence is enigmatic.

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This article reviews the development of the study of relationship between the earth's rotation and the spatio-temporal distribution of global seismicity by stationary model of seismicity rates and annual seismic energy released. Observed variations of seismic energy release in shallow, intermediate and deep focus earthquakes and their frequency distribution confirms this correlation. The peaks of these parameters are controlled by the earth rotation. There exists a phase relationship among earth's rotation rate minima and maxima with the maxima (peaks) of the above parameters as well as Thrust (T) and the strike slip (S) dominating periods of global seismicity. In order to compare our results with observations, the space-time dependence of the frequency of earthquakes and annual energy release has been established. The results are in very good agreement with previous studies and further enhance our knowledge for global seismicity distribution.

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Several recent studies show the possibility of an important connection between the Earth's rotational motion  and the number of earthquakes (Stavinschi and Souchay 2001, Shanker et al. 2001). We discuss the long-term periodic variations (30 years and 60 years) in these two geophysical processes, as well in solar activity and the Sun's celestial orbit. The similarities in such periodicities suggest that solar system dynamics may contribute to both solar and geophysical phenomena.

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The ways by which earthquakes could influence the Earth's rotation and, in a reciprocal way, the Earth tides could possibly trigger earthquakes have been investigated by many authors for more than one century.  After summarizing studies ranging among the most prominent ones on the topic, we present an example of statistical results related to tide-earthquakes correlations starting from a database concerning a specific seismic area, the Vrancea fault located in Romania.

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Mars Orbiter Laser Altimeter (MOLA) team discovered “the striking difference” in elevation between northern and southern hemispheres: “on Mars, the South Pole lying about six km higher than the North Pole, … the planet’s center of mass (is) 3 km north of its geometric center” (Physics Today, Oct 1999, p. 34). The same topography we have for solid Earth: low Arctic and high Antarctic with the same difference 5–7 km. No sound explanation of NS asymmetry was proposed: impact, planetary evolution, mantle convection … are rather artificial and vague. Meanwhile, NS asymmetry is inherent property of any freely rotating flexible celestial body as it follows from Kozyrev’s Causal or asymmetrical mechanics. Relations of Causal mechanics are supported by experimental study of vertical component of causal force by weight change measurement of rotated gyroscope and the study of its horizontal component by pendulum deflection measurement. Kozyrev made measurements at latitudes φ from 45° to 84° and proved that causal force is directed along Earth rotation axis: to the North for φ < 73° and to South for φ > 73°. The magnitude of causal force has order (1–5) × 10−5 of gravity force.

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