The seismic risk in Istanbul: An innovative assessment method

Over the last century, an unprecedented settlement expansion, generated by an exceptional world population growth, has made cities all around the world always more prone to disasters. Natural phenomena, such as earthquakes, could be potentially more dangerous when hit megalopolis and their neighborhoods particularly fragile. Amid the most important global cities, Istanbul is characterized by one of the highest levels of seismic risk. Within its territory, there are numerous highly vulnerable neighborhoods. Some of them are located around İstiklal Caddesi, famous pedestrian street, which is being visited by a great number of people (both Turkish city-users and international tourists) twenty-four hours a day, seven days a week. Part of the old and historical neighborhood of Pera/Galata, in the today’s Beyoğlu Belediyesi, it is a highly attractive zone full of economic activities, acting as heart of the city. Since the importance of this area, its specific seismic risk has been assessed using two different approaches, one traditional and one proposed by the author, which have provided two different responses. The “standard method”, based on generic variables applicable to the whole Istanbul Metropolitan Municipality, shows how this zone is not amongst the most risky area of the city. Whereas, “the experimental method”, calibrated on more precise information and more specific variables typical of the case study area, demonstrates that the level of seismic risk is significant. Finally, a scheme of urban/district emergency evacuation system is here proposed indicating some shelter areas and classifying the streets, inside the case study area, according to their level of safety.