problems addressed by the project - 株式会社オリエン … fault distribution, topography,...
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Sector Disaster Management Planning
Project Type Development Study
Project Title The Study on Disaster Prevention and Mitigation Basic Plan
Location Istanbul, Turkey
Client Director of Soil and Earthquake Research, Istanbul Metropolitan Municipality / JICA
Project Period March 2001 – November 2002
Problems addressed by the Project
In 1999, two large earthquakes hit Izmit and Adapazari in Turkey causing tremendous physical damage and casualties. The earthquakes were triggered by North Anatolian Fault (NAF), which has an extremely large fault line of 1,000 km length, extending from east to west in northern Turkey. Historically, many strong earthquakes have occurred along this fault with epicenters migrating from east to west along NAF. Istanbul, situated on the west end of NAF, is clearly at risk. In spite of well-established seismic research in Turkey, administrative integration for earthquake disaster management is scarce and urban structures are hardly earthquake resistant. Hence, the Government of Turkey urgently requested the Government of Japan to produce a detailed assessment of vulnerability to earthquakes in Istanbul and propose countermeasures to mitigate the disastrous damage.
Service Provided
OC Global used the micro-zoning technique to assess vulnerability to earthquakes in the Istanbul urban area. The earthquake damage estimation and vulnerability assessment were conducted with the aid of GIS using the following obtained data:
Natural Conditions: Waveforms of past earthquakes, geology, fault distribution, topography, slope distribution, boring data (existing and 48 new drillings conducted in the project)
Social and Physical Conditions: Census data, cadastral data for buildings, public facilities, lifelines, landuse, road networks, sub-district boundaries
Based on actual damage of past earthquakes in Turkey, OC Global conducted evaluation of liquefaction potential, slope stability and fire outbreak, and comprehensive damage estimation as to casualties, buildings (including 2 schools with detailed seismic diagnosis), 480 bridges, lifelines (water supply, sewage, gas, electricity), road networks and port. In the worst earthquake scenario, an estimated 87,000 deaths and 13,500 casualties would occur.
In order to make effective and substantial project proposals for urban rejuvenation, OC Global conducted vulnerability assessment of urban structures in Istanbul covering the relationship between urban disaster damage and building structure, urban development and renewal trend in Istanbul, landuse texture, intricate road networks, parks and open spaces availability.
Project Recommendations
In the short term, priority was put on implementation of strengthening projects for public buildings and facilities, infrastructure and lifelines, and establishment of a disaster management center, given that the physical strengthening of structures is the most effective approach to mitigate the direct earthquake damage. As medium- to long-term measures, OC Global recommended the following works after or parallel to undertaking of physical improvement:
Area-wide redevelopment with value-added landuse scheme Promotion scheme for constructing seismic resistant building with financial credit system Systemic reorganization for disaster management sector Promotion of public awareness of earthquake disaster