IN DEFENSE OF ZEYTINBURNU GUNEY OZCEBE, HALUK SUCUOGLU, M. SEMIH YUCEMEN AND AHMET YAKUT Department of Civil Engineering, Middle East Technical University, 06531, Ankara, Turkey In the past, severe earthquakes that affect urban environments in Turkey and elsewhere caused extensive losses of life and property. In many countries, even medium size events occurring near densely populated areas may lead to considerable casualties and economic losses. This also applies to the developed regions of the world. For instance in the last 15 years, almost 5,000 people have died in earthquakes occurring in countries of the European Union. The 1980 Irpinia Earthquake, with a magnitude of 6.9 in Richter scale, struck Italy, killing 4,580 people and leaving 250,000 homeless 1 . More recently, on 7 September 1999, an earthquake of magnitude 5.9 in the Richter scale hit Athens. After a week of search and rescue, 143 people were confirmed dead, either in collapsed buildings or by falling elements of buildings or by heart attacks, while 85 were extricated from the ruins. In this event more than 750 people were injured and thousands of households became homeless. In the 1999 Kocaeli earthquake (Richter magnitude of 7.4) the poor performance of vulnerable buildings claimed more than 20,000 lives. In monetary terms these events caused losses equivalent to 6.8%, 2% and 6.5% of the corresponding GNP of the above mentioned countries in the respective years. These examples emphasize the high vulnerability of the urban environment in earthquake prone regions. The built environment of Istanbul alone consists of about 1,000,000 buildings. It is anticipated that some 50,000 to 70,000 buildings in Istanbul are expected to experience severe damage or collapse if the probable scenario earthquake occurs. 2 Considering that Istanbul is under very high seismic risk, occurrence of an earthquake with a magnitude of 7 or more in Richter scale would cause a serious burden on Turkey’s development. Similar risks, in varying extents, do exist in cities like Athens, Naples, Lisbon, Skopje and Bucharest. These risks, threatening the sustainable development of communities, have to be reduced by effective measures that are economically feasible and socially acceptable seismic risk mitigation methodologies. Since the main cause of casualties and other losses during past earthquakes is the poor performance of existing substandard buildings, determination of the addresses of the seismically vulnerable buildings within the existing building stock is a high priority task in the seismic risk reduction of the urban environment. Over the last decade, a lot of efforts have been devoted to the problem of how to devise reliable estimates, given the large uncertainties in the pattern of earthquake occurrence, both in time and space and our limited understanding of behavior of the vulnerable elements of the built environment 3 . Because of various uncertainties and randomness involved both in seismic demand and capacity, in some of these studies, assessment of potential damage is based on statistical and probabilistic techniques. Current approaches in seismic vulnerability evaluation methods follow three main stages. These stages are namely: Walk-down evaluation, preliminary evaluation and final evaluation. Evaluation in the first stage does not require any analysis and it relies on the past performance of similar buildings. The goal of the walk-down evaluation is to 1 http://europa.eu.int/comm/research/leaflets/disasters/en/earthqu.html 2 JICA Report (2002). The Study on a Disaster Prevention/Mitigation Basic Plan in Đstanbul Including Seismic Microzonation in the Republic of Turkey. 3 Benedetti, et al., 1988; Brookshire, et al., 1997; Dolsek and Fajfar, 2001; Dowric, et al., 1997; Gavarini, et al., 1990; Gurpinar and Yucemen, 1980; Hassan and Sozen, 1997; Hwang and Huo, 1994; Kircher, et al., 1997; McCormack and Rad, 1997; Wen et al., 1994; Whitman, et al., 1997