Investigation of meteorological effects on strain measurements at two stations in Hungary

Analysis of extensometric and meteorological data from two observatories (Sopron and Pécs) in Hungary were carried out in order to investigate and to compare the stability of a deep and a surface observatory against the influences of temperature and air pressure variations. Long-term periodical variations of extensometric data, tidal analysis of the extensometric data and calculation of coherence between extensometric and air pressure data were applied as tools of comparison. Investigational results support the assumption that a deep observational site is less sensitive to the variations of the meteorological parameters than a surface one. The coherence calculations show unambiguously that the deformation measurements are less disturbed by air pressure variations especially of some days periods due to the weather system and the average noise level at tidal and higher frequencies is lower at the deep registration site than in the case of the near surface observatory.