Geodetic and Geophysical Institute, RCAES, HAS

Geodynamic Observatory Sopronbánfalva (Sopron)

The Geodynamic Observatory was built for monitoring various geodynamic phenomena in 1961. The Observatory is about 5 km far from the centre of Sopron, in the garden-city Sopronbánfalva. Its coordinates are: latitude: 47.7 N; longitude: 16.5 W. The Observatory is an artificial tunnel driven in gneiss. The thickness of the rock above the tunnel is about 60 m.

In the first time the Observatory was used for recording solid Earth tides by horizontal pendulums with capacitive transducer and by a GS-11 field gravimeter equipped also with a capacitive transducer. Both instruments were developed in the Geodetic and Geophysical Institute (GGI) Research Centre for Astronomy and Earth Sciences of the Hungarian Academy of Sciences. Recently these instruments are out of use, but thanks to a current development the problem of continuous gravimetric tidal recording has been solved by an LCR G gravimeter. Now the instrument is being operated in Piszkéstető at the seismological station PSZ by the financial support of OTKA K101603 project. The regularly updated graphs of the tidal records and auxiliary data can be seen here.


In 1990 a quartz tube extensometer with a length of 22 m was installed in the gallery of the Observatory. This instrument was developed in the frame of a scientific cooperation between the Geophysical Institute of Moscow and the GGRI in Sopron. The distance of the extensometer from the entrance is about 30 m. The instrument is thermally insulated and separated by three doors from the outer environment. The annual temperature variation in the gallery near the instrument is less then 0.5 °C and the daily variation is about 0.05 °C. It means that the Observatory ensures a very stable observation place for continuous Earth tides recording and for monitoring tectonic deformation.

Beside the extensometer a microbarograph is operating in the Observatory. It is used for recording air pressure variations caused by lunisolar effects. On the basis of microbarograph measurements connections between various geodynamic phenomena and barometric pressure variations are investigated.

The Observatory is part of the Hungarian seismological network. Therefore a three component seismological station is working in the Observatory. Seismological data are automatically transferred via telephone line to the Department of Seismology of the GGRI to Budapest.

A Sopronbánfalvi Geodinamikai Obszervatórium épülete
A Sopronbánfalvi Geodinamikai Obszervatórium alaprajza