Results of tidal research

At the Geodetic and Geophysical Research Institute of the Hungarian Academy of Sciences the tidal research was started in the mid-sixties of the last century. At first, measurements by horizontal pendulums (Tomaschek-Ellenberger, Melchior) were car- ried out. At the beginning of the 70’s a new horizontal pendulum with capacitive transducer was developed. By means of this pendulum tidal measurements were car- ried out at the Geodynamical Observatory in Sopronb ́ anfalva and local geodynamical movements were monitored in a coal mine in P ́ ecs and at our nuclear power plant in Paks. At the beginning of the 90’s a quartz tube extensometer with capacitive trans- ducer was installed at the Geodynamical Observatory in Sopron and in the uranium mine in P ́ ecs. The extensometers in Budapest installed in the early 80’s, the exten- someter in V ́ yhne (Slovakia) were mounted with capacitive transducers. New, in-situ calibration method was developed at our institute and all of these extensometers were recalibrated by the new calibration device. A microbarograph of high resolution was also developed for the study of at- mospheric tide in 1991. The investigation of the connection between air pressure variations and geodynamical phenomena has been carried out since 1992. This paper presents the developed instruments and the results obtained by these instruments