Evaluation of earthquake risk parameters in the historical site of Istanbul

Seismic risk assessment requires data from different levels which present both hazard and vulnerability of a city or a region. Urban areas have complex structures to explore the inter-relationships of physical, social, demographic and economic features. Moreover, there is always a chain reaction among urban components which causes some difficulties to assess them. In large metropolitan areas, the urban pattern shows heterogeneity; hence, while calculating the earthquake risk levels of a city, it is vital to distinguish data indicators with the respect of zones' properties. In the earlier research by Kundak earthquake risk parameters in Istanbul were produced and examined to reveal their loadings on relative risk levels [1]. Their findings point out that the parameters are able to explain the risk levels about 67.3%. The aim of this paper is to evaluate the seismic risk parameters in the historical part of the city which had been witnessed several medium and big sized earthquakes. The results illustrate that the risk parameters are corresponding to the seismic risk with an explanation level of 76.2%. Furthermore, the rank and the formation of the main factors are considerably different from which had been observed in city wide. The findings of this study and the comparison of findings with the former one, show that (1) the database selection is important to calculate the total risk, (2) beside macroscopic approaches, it is necessary to evaluate sub-regions of the city according to their features and (3) investigations on historical sites can help to validate the seismic risk estimations.