DBPapers
DOI: 10.5593/SGEM2014/B12/S2.073

LIQUEFACTION PROBABILITY IN BUCHAREST AND INFLUENCING FACTORS

A.Bala, D. Hannich, D. Ehret, G. Huber
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-08-7 / ISSN 1314-2704, June 19-25, 2014, Book 1, Vol. 2, 573-580 pp

ABSTRACT
Bucharest, the capital of Romania with about 2.5 million inhabitants, is frequently struck by intense, damaging earthquakes (in recent years in 1940, 1977, 1986 and 1990). In 1995 a Collaborative Research Center 461 (CRC-461) entitled: “Strong Earthquakes - a Challenge of Geosciences and Civil Engineering” was established in July 1996 and ended in December 2007. It was funded by the German Research Foundation and supported by the State of Baden-Württemberg, as well as the University of Karlsruhe (TH), actually Karlsruhe Institute of Technology (KIT). The CRC aimed strategic research in the field of strong earthquakes with regional focus on the Vrancea seismic events in Romania. Between 1995-2007 several research works were done in Romania, with the support of several Romanian research institutes and the University of Bucharest. One of the research questions was, if liquefaction can occur during strong earthquakes within the shallow sandy layers in Bucharest. As known, strong earthquakes can cause, under certain geologic conditions, liquefaction and therewith ground failure as sand boils, lateral spreading, or differentiated subsidence. Thus in 2005 a research work begun to analyze the liquefaction risk for Bucharest. For this purpose, at 10 representative sites in Bucharest, Seismic Cone Penetration Tests (SCPTu) were executed. An area-wide evaluation of the liquefaction probability in Bucharest was established. The “factor of safety” (Fs) against liquefaction and the “probability of liquefaction” (PL) were computed from the obtained test-data. For the first time, maps of the “liquefaction potential index” (Li) and of the “liquefaction severity index” (Ls) for Bucharest were outlined. These maps show how severe liquefaction phenomena can occur during strong Vrancea earthquakes in Bucharest.

Keywords: hydrogeologic conditions, liquefaction probability, maps of liquefaction hazard in Bucharest City, strong earthquakes.