F. Wenzel - Geophysical Institute, Karlsruhe University, Germany,

The hazardous earthquakes for the Romanina capital Bucharest are the intermediate depth Vrancea events between 80 and 200 km depth, 130 km N of the city. Due to this geometry ground motion variations in Bucharest must be dominanted by the site effects. Thus ratios of Fourier Amplitude Spectra with the records of a reference stations in the denominator contain only site effect terms and should not vary significantly for different Vrancea sources. However,this prediction of the source-site separation model of earthquake wave generation and propagation is clearly incorrect for Bucharest. Our conclusion ist that (a) this model is incorrect or incomplete, and (b) as a significant amount of aleatory uncertainty always exsists in site effects so that they should be quantified in probabilisic terms.