VERTICAL MOVEMENTS ON THE TERRITORY OF TALLINN

Abstract

Studies based on repeat levelling performed in the city of Tallinn show local earth surface deformations in the area of ancient valleys buried under quaternary sediments. Until 1964, the highest rate of sinking (up to 30 mm/year) was observed in the area south of Tallinn Old Port until Liivalaia Street. The maps of vertical movements drawn up on the basis of earlier levelling data indicate local sinking in the region of the city centre since 1951. From 1964 onwards, the intensity of the sinking has been steadily decreasing. The data obtained from the latest levelling works show that the sinking of the area under study has stopped or reversed into rising (up to +0.4 mm per year). Sinking of Tallinn is connected with the geological structure and ground water level.