Author(s)

ORSOLYA KEGYES-BRASSAI

Abstract

The process of carrying out an earthquake risk assessment of a town can provide important data for authorities and disaster management to better understand risks to many buildings rather than a single building. This is even more important in the case of moderate seismic areas where any mitigation measures to be taken should be justified by seismic risk determination. Moderate seismicity does not necessarily equate to moderate damage from earthquakes. Vulnerability to earthquakes even increases with extending urban areas. Seismicity in the Pannonian Basin is moderate compared to seismicity of surrounding areas, nonetheless, reports of major earthquakes in Hungary often refer to heavy building damage and liquefaction (e.g. 1763 Komarom earthquake). Gyor was chosen to be the examined area for seismic risk analysis because it is the most important city of northwest Hungary with a large number of monumental buildings and a complex geological and geographical settings. In order to make the best use of limited resources usually characteristic to moderate seismic zones, the presented method used existing soil data, rapid visual screening of buildings, a limited number of field tests and free, but sophisticated, software. This paper focuses on the results of vulnerability analysis of buildings; however, it considers the results of seismic hazard and local site effects based on response analysis with more than 6000 realizations. Vulnerability of the buildings with different structural types were evaluated based on a rapid visual screening of 5000 building. Vulnerability based on visual screening was compared to a pushover analysis of the typical constructions. As one would expect, since the hazards and vulnerabilities were not uniformly distributed in the city districts of Gyor, there were zones of higher and lower risk. These results can then serve as useful tools for decision makers and can be applied directly to risk management plans.

Keywords

vulnerability assessment, rapid visual screening, pushover