Earth crust vertical movements according to ITRF2000, ITRF2005, ITRF2008 and ITRF2014 coordinate systems and their comparing analysis

Abstract

The analysis of Earth’s crust movement vertical velocities was made both for separate regions, and averaged on regions. As input data coordinates and velocities of earth crust points, obtained in International Coordinate Systems ITRF2000, ITRF2005, ITRF2008 on the base of processing radio interferometric (VLBI), laser (SLR), Doppler (DORIS) and GPS observations was used. For the purpose of global analysis all input velocity values were averaged in the х trapezoids. For filling trapezoids the spherical function expansion to N=36 was made. Expansion harmonic coefficients allowed determine the global characteristics of earth crust movements both for all Earth, and for separate hemispheres, polar and equatorial regions, continents and oceans. It appears, that polar regions were risen, and equatorial ones were lowered, that can indicate the modern Earth oblateness reduction. The constructed maps of vertical velocities were compared with obtained by us map of earth crust strain distribution. It is appeared, that regions of modern earth surface rising (Fennoscandia, Canada, Antarctica) coincide with regions of vertical extension strain, and the lowering regions – with compression regions. Simultaneously with the determination of harmonious coefficients the mean-square error of approximation for expansion of power n=1 N and power dispersion were determined. Whereas the results converge badly and dispersion increased with the n grows, hence we can concludes, that vertical movements do not characterized global earth crust movement and denotes the unrelated character of these movement. Seemingly, the main cause of such movement origin is the local seismic events (earthquake, volcanic eruption and so on). It confirms by our conclusions about correspondence of vertical strain maximal gradient (and therefore vertical velocities) map of the earthquake distribution. In work the detailed analysis of obtained results for separate Earth’s regions was made.