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SEISMIC HAZARD IN THE PANNONIAN REGION

Seismic hazard for single sites and hazard maps for the whole Pannonian region (44.0-50.0N; 13.0-28.0E) have been calculated. The hazard assessment was carried out using a probabilistic approach by incorporating a wide range of parameter values and viable interpretations that were consistent with the data. Alternative interpretations were described by branches of a logic tree. Each branch was weighted according to the ability of that interpretation to explain the available data. The resulting seismic hazard map describes expected shaking with a 475-year return period in terms of peak ground acceleration. Furthermore, some important contributors to seismic risk are highlighted, and a liquefaction hazard map is presented for the territory of Hungary.

Seismicity of the Pannonian Basin

This article gives a brief summary of the seismic instrumentation used and the monitored results of earthquake activity in Hungary. Despite the Pannonian basin being characterized as a low-to-medium level seismicity region, the risk of destructive earthquake is still a major concern throughout Central Europe. The high population density in the region, and the number of vulnerable industrial facilities eg. nuclear power plants are being among the most sensitive ones regarding public concern.

Computer estimation of intensities: The 1985 Berhida, Hungary, earthquake

In this paper a computerized method for the intensity estimation from macroseismic observations is presented. The successive steps of the MSK intensity scale (2° to 10°) receives weights according to the observations marked on the earthquake questionnaires. These weights are summed for the individual scale steps. The distribution of these summed weights and their relation to an experimentally chosen function of the criterion make it possible to estimate the appropriate intensity value and its reliability. By computer evaluation of earthquake reports an objective comparison of estimated intensities given by different seismologists can be made, provided that uniform earthquake questionnaires are used. The application of this method will result in more homogeneous intensity data.