Abstract
The paper discusses the horizontal movements of the Earth's crust in the territory of Lithuania. The curves of horizontal deformations are found by comparing the changes in coordinates of geodetic network points obtained after repeated measurements carried out after a certain period of time. The goal of the investigation was to analyse the regularities of indications of horizontal movements of the Earth's crust established according to the data of three different geodetic measurements. The parameters of horizontal movements were calculated using the method of finite elements and applying tensor analysis. To implement the investigation in the territory of Lithuania, the authors used 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 (the total of 45 joint points). After the investigation, new curves of 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 case of the analysis of obtained results, 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 were observed at the boundaries of deep blocks of the lithosphere.
Highlights
Investigation of the Earth’s crust movement is a topical problem that is related with formation and use of geodetic networks and with identification of seismically active territories, forecasting of seismic activity of tectonic faults, construction of environmentally hazardous objects and prospecting of minerals (Stanionis 2005).Up to the beginning of the last decade of the 20th century, the attention of the world was focused on movement of the Earth’s crust in seismically active territories (Anikienė 2008)
In the territory of Lithuania, points of the triangular geodetic network were formed in the year 1942; while points of the GPS network of the class 0 and the class 1 were formed in the year 1993 and repeatedly measured in the year 2007
For verification of the reliability of the available data and assessment of the regularities of the indicators of horizontal deformations of the Earth’s crust obtained from the data on measurements in three epochs according to joint points of the triangular and GPS networks, a scheme of a network for repeated measurements consisting of 69 finite elements other than provided in works by Zakarevičius 2003 and Stanionis 2005 is required (Fig. 1)
Summary
Investigation of the Earth’s crust movement is a topical problem that is related with formation and use of geodetic networks and with identification of seismically active territories, forecasting of seismic activity of tectonic faults, construction of environmentally hazardous objects and prospecting of minerals (Stanionis 2005). It was supposed that no noticeable quakes can occur in platform regions of low seismic activity (up to the magnitude 3 according to the 12point scale). In Lithuania, more serious interest in seismic risk zoning was taken after the earthquake in Osmussaare (Estonia) with the magnitude 6–7 (according to the 12-point scale) in the year 1976 (Ilginytė 1998) and the Carpathian earthquake in Romania in the year 1977. In the latter region, quakes were perceptible in the years 1986 and 1990 as well. The investigation aimed to analyse the regularities of the indications of the horizontal movements of the Earth’s crust established according to the data of three different geodetic measurements
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
