Analysis of preparedness and response to earthquake risk of Beşiktaş district using GIS

Abstract

For years Turkey is placed in a higher position among the countries that have been struck with loss of life and property due to earthquakes. Location of Turkey is the most important reason for this situation, since it is located on an active seismic belt. Being the economical, cultural and industrial centre of the country, Istanbul has a considerably high earthquake risk since the North Anatolian Fault Zone extents through the Marmara Sea. Considering the historical earthquakes especially Kocaeli Mw:7.4 in 1999, and the structure of the North Anatolian Fault Zone, it is estimated that the occurrence probability of an earthquake, bigger than Mw: 7.0 in the next 30 years is approximately 70 per cent. Furthermore the earthquake risk increases due to the rapid, unplanned urbanization and building construction that damages the specifications in Istanbul. Considering urban structuring in Istanbul, it has been concluded that connected districts have different characteristics. That is why the need of a comprehensive damage mitigation plan which is based on detailed earthquake hazard analysis emerged. The aim of this study is to investigate the preparedness and response levels of Besiktas district for a possible earthquake using the Geographic Information Systems and carrying out the analyses that will form a base for extensive damage mitigation plans. Within this concept, the earthquake risk for houses and business units located on Besiktas district is determined using a scenario earthquake which is obtained from Kandilli Observatory and Earthquake Research Institute Earthquake Engineering Department and a hazard assessment was determined by using the geological formation and seismic activity evaluations of the field. Additionally, estimation of the casualties in terms of damage probabilities by determining the building stocks, structural characteristics of these buildings (wood, steel, reinforced concrete etc.) and number of stories has been performed. A data infrastructure has been prepared for the planning activities which will be produced by using these analyses. In this way, the determination of the most appropriate meeting and tenting areas after an earthquake and the determination of the closest health care centers for injured people were practiced in this study.