DBPapers
DOI: 10.5593/SGEM2014/B11/S5.065

IMPROVED METHODOLOGY TOWARDS A QUANTITATIVE ASSESSMENT OF SITE EFFECTS EMPLOYING GEOPHYSICAL AND SEISMOLOGICAL DATA

A. Bala
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-07-0 / ISSN 1314-2704, June 19-25, 2014, Book 1, Vol. 1, 489-496 pp

ABSTRACT
The evaluation of seismic hazard and mitigation of the seismic risk is one of the permanent and urgent problems facing the Romanian society, equally implying work of seismologists, geologists and engineers. Significant efforts were made to predict the peak values and spectral characteristics of the strong motion in large urban areas, like Bucharest. At the same time, important efforts were made to determine the site effects and microzonation maps for the same city. Bucharest, the capital of Romania, with more than 2 million inhabitants, is considered after Istanbul the second-most earthquake-endangered metropolis in Europe. Four major earthquakes with moment-magnitudes between 6.9 and 7.7 hit Bucharest in the last century. The most recent destructive earthquake of 4-th March 1977, with a moment magnitude of 7.4, caused about 1.500 casualties in the capital alone. All disastrous earthquakes are generated within a small epicentral area – the Vrancea region - about 150 km north of Bucharest. The present study will lead to an improved methodology of assessment of local seismic hazard (microzonation) of sites of specific interest. It is already known that, from January 2011, all EC countries are obliged to implement the Eurocodes. Eurocode 8 deals with Earthquakes. The existing European Building Code Eurocode 8 (http://eurocodes.org.ua/) must be critically reviewed by specialists in each country and improvements should be suggested in order to adapt it to the Carpatho-Balkan region and to the specific seismic hazard in Romania. This paper will introduce an improved and updated methodology of seismic hazard evaluation (microzonation) of relatively low cost and suitable to be applied in large cities or at industrial objectives of national interest, like nuclear power plant of Cernavoda, big dams, industrial constructions, etc. This will be a direct contribution to reduce the seismic risk and towards an improved seismic safety in large cities, like Bucharest City, capital city of Romania.

Keywords: destructive earthquake; improved methodology of microzonation; site effects.