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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:25 |
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Conference: Bucharest University Faculty of Physics 2001 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
ATTEMPT ON SEISMIC MICROZONING OF BUCHAREST.
A DETERMINISTIC APPROACH
Authors:
Gh.Marmureanu*, Carmen O. Cioflan*, B.F.Apostol*
Affiliation:
* National Institute for Earth Physics, P.O.Box MG-2, 76900, Magurele, Bucharest
E-mail
Keywords:
Abstract:
The mapping of the seismic ground motion in City of Bucharest, due to the strong Vrancea earthquakes is carried out using a complex hybrid waveform modelling method that allows easy parametric tests. The hybrid method combines the modal summation technique, valid for laterally homogenous anelastic media, with finite-difference, and optimizes the advantages of both methods. For recent Vrancea earthquakes when strong motion observations are available, it is possible to validate the modelling by comparing the synthetic seismograms with the actual records. The realistic modelling of the seismic input has been applied to a first-order seismic zoning of the whole territory of the Bucharest area. Even though it falls in the domain of the deterministic approach, the method is suitable to be used in new integrated procedures, which will combine probabilistic and deterministic approaches and allow us to minimize the present drawbacks, which characterize them when they are considered separately at least to Bucharest area. Using the hybrid method with a couple-double seismic source approximation and relatively simple path (bedrock) and local structure models we succeeded in reproducing the recorded ground motion in Bucharest, at a very satisfactory level for seismic engineering, in the frequency range (0.05 –1) Hz for the case of May 30, 1990 Vrancea earthquake. This is one of the most important steps in the seismic zonation, because the synthetic seismograms and the derivated quantities of engineering interest are able to supply the absence of recorded data for the strong motion in Bucharest.
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