Urban Transformation as a tool for Disaster Mitigation

Urban transformation projects are prepared with the purpose to sanitize decayed areas, to make cities beautiful and to create economic vitality. Since natural hazards threaten large metropolitan areas, urban transformation is pronounced together to mitigate disasters. This approach of urban transformation includes land use decisions related to hazard, risk and vulnerability analysis and to enhance the implementation of building codes respecting the current standards with application of urban transformation methodologies. Ideally urban transformation methodologies include not only physical and economic improvement but also provide social improvement concerning people who live in the area. Urban transformation seems to be the government’s primary tool for disaster mitigation by guiding urban development and improving the quality of housing stock in Turkey. Several attempts since 2005 to pass a bill to institutionalize this controversial strategy finally succeeded in 2010. In June, Law No. 5998, an amendment to Municipal Law No5393 of 2005, expanded item 73 on urban transformation projects to give municipalities the power to initiate Urban Transformation projects to rehabilitate urban areas or to mitigate disaster risk. According to this item in metropolitan areas, district municipalities can implement such projects within their jurisdictions with the approval of the metropolitan municipal council. Therefore Istanbul (Turkey) which is the biggest metropolitan area and waiting a big earthquake in next 30 years will be subjected to several urban transformation projects in the near future. In the paper, the urban transformation related to disaster mitigation approach will be discussed in the case of Istanbul in terms of descriptive analysis and proposals for future development.

Assessment of Seismic Risk in Istanbul

The 1999 earthquakes occurred in Turkey caused destructions in every field and level in nation wide with the high number of deaths and injuries, the remarkable rates of collapsed and heavily damaged buildings and the interruption of business activities in long-term. In the last 5 year-period, various scientific researches focusing on seismic issues have investigated the relationships among seismicity, site conditions and vulnerability. Moreover, with the co-operations of central and local governments, universities and international agencies, many comprehensive projects have been carried out, such as “A Disaster Prevention/Mitigation Basic Plan for Istanbul” by Istanbul Greater Municipality - Japan International Cooperation Agency. Despite 1999 earthquakes had slight effects on Istanbul, the probability of a great earthquake (estimated to occur up to 30 years), has accelerated the attempts on risk evaluation, development of mitigation strategies, readjustment of disaster management system and so on. The primary studies on this field are focused on understanding seismicity and site conditions at large scale so that the earthquake maps produced show risky zones related to geological indicators. Aftermath of many great disasters, it has been observed that land-use decisions, demographic and economic pattern are the key components which increase or decrease the vulnerability level of settlements. In this context, the aim of this paper is to evaluate vulnerability components affecting risk levels and to explore risky zones of Istanbul. In this paper, urban and seismic indicators (i.e. site conditions, demography, land use, economy) have been aggregated and factor analysis has been used in order to reveal principal components of earthquake risk in Istanbul. According to these main factors, using cluster analysis, the critical zones of Istanbul have been indicated on urban pattern.