NICOLAE MÂNDRESCU, MIRCEA RADULIAN, GHEORGHE MARMUREANU
National Institute for Earth Physics, P.O. Box MG-2, 077125, Bucharest, Romania
Reconsideration of previous information and results allows us to investigate how near-surface geological units of Bucharest area play a role in determining ground motion response in period bands that are of engineering significance. The superficial deposits within the study area are entirely Quaternary. Lithological information has been compiled from geological, geotechnical and hydrogeological boreholes. The predominant periods of oscillation of the subsurface layers over Bucharest territory have calculated values between 0.9 and 1.9 s, increasing from south to north, in correlation with the constant increasing of the thickness of the Quaternary cohesionless deposits. They are accurately matching the results obtained by seismological studies using seismograms of Vrancea moderate-magnitude earthquakes, recorded at Bucharest seismic station.
Key words: predominant period, cohesionless deposits, Bucharest, Vrancea subcrustal earthquakes.