Strain and stress fields of the Ignalina NPP area from GPS data and thin-shell finite element modelling, NE Lithuania

Sliaupa S., Zakarevicius A., Stanionis A. Strain and stress fields of the Ignalina NPP area from GPS data and thin-shell finite element modelling, NE Lithuania. Geologija. Vilnius. 2006. No.56. P. 27–35. ISSN 1392-110X Horizontal movements of the Earth’s surface were measured in a GPS network in the Ignalina NPP area. The network consists of ten GPS sites established in 1998. It was designed according to the known tectonic framework. Two cycles were carried out in September 1998 and September 1999. The modelling of crustal deformations and stresses was performed using a thin-shell finite element modelling (FEM) technique (ANSYS). A significant tectonic strain was recognised in the Ignalina NPP area. The stress field shows variations in the network controlled by the large-scale Drūksiai fault trending west–east. Three major blocks are defined in the area, showing differential movements as high as 10 mm/a. The defined tectonic stress level reasonably explains the earthquake activity in the Baltic region. The principal maximum stress in northeast Lithuania is suggested to be oriented NNE–SSW. The modelling results reasonably explain the earthquake activity potential of the Baltic area.

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