The realization of a semi-kinematic datum in greece including a new velocity model

Abstract

The current geodetic network in Greece, which is realised by both the official Hellenic Geodetic Reference System of 1987 (HGRS87) and the GPS permanent network of the contemporary static Hellenic Terrestrial Reference System of 2007 (HTRS07), experience significant inhomogeneous ground displacements. As time passes, the distortion of both networks results in increasing degradation of positioning accuracy and datum stability. For these reasons the velocity field of the Earth’s crust in Greece has to be rigorously estimated and taken into account. In order to achieve a stable geodetic datum, independent of time and coping with the problems of the serious inhomogeneous crustal displacements, the implementation of a semi-kinematic datum for Greece is proposed. The new datum will be referred to a specific epoch, absorbing crustal displacement using an estimated velocity model. This model has been created by dividing Greece into stable crustal blocks by applying the Euler Pole model and statistical criteria. In addition the Least Squares Collocation was applied at the residuals of Euler Pole model in order to predict the previous estimated residuals separately for each one block, integrating in this way the new estimated velocity model.