Earthquake risk modeling for evaluation of different
mitigation measures to reduce losses to property owners in the
metropolitan area of Shiraz, Iran

Mehdi Sadeghi explains the outcome of his YSSP project work on risk modeling of the structural vulnerability of buildings due to earthquakes in Iran.

M. Sadeghi

M. Sadeghi

Introduction

Iran is in a highly seismically active region, and structures must be designed and constructed to withstand earthquakes based on the real earthquake risk. Lessons learned from past earthquakes show mitigation to be a key element in reducing structural and human losses. A vital role in risk management studies is also played by loss estimation. This is because property values change - as do the costs of repair and replacement, building materials, design, and practice - along with changes in building codes.

Methodology

This study describes economic and human losses related to seismic hazard using two approaches: i) Earthquake Risk Modeling and ii) Probabilistic Benefit-Cost Analysis. Earthquake risk modeling has been designed and implemented in GIS based on four main modules: hazard, exposure, vulnerability, and loss. The hazard module characterizes the risk of earthquake hazard by its epicenter location and moment magnitude, plus other relevant parameters. The exposure module characterizes as accurately as possible the inventory or portfolio of properties at risk. In the vulnerability module, the model quantifies the physical impact of the earthquake hazard on the property at risk. The loss module includes the cost of repairing and/or replacing a structure. Probabilistic benefit-cost analysis (BCA) was conducted with two focuses: economic and human losses.

Results

According to the results of benefit-cost analysis obtained in 53 different types of buildings, ratios over one are related to the pre-code buildings in all types of structure (steel, concrete, and masonry). Benefit-cost ratios for the steel, concrete, and masonry moderate-code buildings are less than one. Structural vulnerability is highly dependent on building codes rather than hazard. The results with respect to human losses show a significant increase in benefit-cost ratios. 

References

Hochrainer-Stigler, H. Kunreuther, J. Linnerooth-Bayer, R. Mechler, E. Michel-Kerjan, R. Muir-Wood, N. Ranger, P. Vaziri, and M. Young (2011) The Costs and Benefits of Reducing Risk from Natural Hazards to Residential Structures in Developing Countries, working paper # 2011-01, The Wharton School, University of Pennsylvania.

Federal Emergency Management Agency (2003), HAZUS_MH MR4 Technical Manual, Washington, D.C.

H. Motamed, B. Khazai , M. Ghafory-Ashtiany , K. Amini-Hosseini (2012) An automated model for optimizing budget allocation in earthquake mitigation scenarios” Nat Hazards. DOI 10.1007/s11069-011-0035-y.

Note

Mehdi Sadeghi, of the Science and Research Branch, International Astronomical Union, is an Iranian citizen/resident in Iran. He received private non-IIASA funded and worked in the Risk, Policy and Vulnerability (RPV) Program during the YSSP.

Please note these Proceedings have received limited or no review from supervisors and IIASA program directors, and the views and results expressed therein do not necessarily represent IIASA, its National Member Organizations, or other organizations supporting the work.


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Last edited: 19 August 2015

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