The analysis of change of the indications of horizontal movements of the earth‘s crust in the territory of Lithuania

Abstract

In the Paper, the horizontal movements of the Earth’s crust in the territory of Lithuania are discussed upon. The curves of the horizontal deformations are found by comparing the changes of the coordinates of points of geodetic network obtained after the repeated measurements carried our after a certain time. The goal of the investigation was an analysis of the regularities of the indications of the horizontal movements of the Earth’s crust established according to the data of three different geodetic measurements. The parameters of the horizontal movements were calculated by using the method of finite elements and applying tensor analysis. For implementing the investigation in the territory of Lithuania, the points of the triangulation network formed in the year 1942 and the points of GPS networks of zero class and first class formed in the year 1993 and measured once again in the year 2007 (total 45 joint points) were used. After the investigation, new curves of the horizontal deformations (such as relative linear deformations, relative shear deformations, relative dilatation, the maximum and the minimum elongation of the key horizontal deformations and the directions of the maximum elongation) were found. In cause of the analysis of the results obtained, it was found that the positive values of deformations predominate in the direction of the maximum related elongation and the negative values of deformations predominate in the direction of the minimum related elongation. The maximum elongation of the key horizontal deformations varies between -1,608·10-6 and 20,832·10-6. The minimum elongation of the key horizontal deformations varies between -29,424·10-6 and 1,397·10-6. Dilatation varies between -27,580·10-6 and -8,612·10-6. It was found that more intensive changes of indications of deformations is observed at the limits of deep blocks of lithosphere.