Earthquake loss estimation for Greater Cairo and the national economic implications

The Egyptian economy and culture are centralized in the Greater Cairo region. Thus, it is essential that the built environment is able to withstand the possible earthquake events that may occur, and to continue to operate and function. Failure to do so would result in significant economic losses. This study presents the latter stages of a multi-tiered probabilistic earthquake loss estimation model for Greater Cairo and builds upon previous studies of the seismic hazard. In order to assess possible damage to the built environment, and the resulting economic losses, the vulnerability of the built environment is first evaluated. Through the use of satellite images, Egypts building census, previous studies and field surveys, a building-stock inventory is compiled. This building inventory is classified according to structural type and height, and is geocoded by district. Using existing fragility curves, the vulnerability of the building stock is assessed. In addition, the vulnerability of both the electricity and natural gas networks are assessed, through the use of fragility curves, cut sets and an evaluation of the supply networks. Based on the assessment of direct losses, the losses associated with building damage far exceed those associated with the considered network infrastructure. A macro-economic model is developed that takes into account damage to the built environment and provides estimates of indirect economic losses, as well as enabling the identification of the optimal recovery process. Using this model, it is shown that the indirect losses can exceed direct losses for extreme scenarios where the economy is brought to a near standstill. The framework developed and presented herein can be extended to include more networks, and is also applicable to other regions.