Zoning earthquake vulnerability using GIS (Case study: Tehran city)

Natural hazards like earthquakes, tornados and floods can cause considerable losses to lives and environmental properties. In order to develop an appropriate risk management and loss mitigation strategy, it is crucial to develop reliable methods for risk assessment. Risk assessment is defined by both assessing the likelihood and intensity of the natural disaster.

In order to assess earthquake vulnerability in this research, governing factors were identified and weighted using Analytic Hierarchy Process (AHP). Vulnerability map for census tracts of Tehran city has been provided with the help of Index Overlay (IO) and Fuzzy Logic methods. Results are presented visually in GIS environment.

The results indicate the preference of fuzzy logic in determining vulnerability of areas, although index overlay method with sufficient number of weight classes for each factor can bring similar results. In addition, index overlay method benefits from simplicity, faster problem solving and more flexibility in combining inputs and ranking outputs. A suitable method for the preparation of vulnerability map must observe the fuzziness rate of parameters, the appropriate selection of membership function and the optimized integration of data layers.