EARTHQUAKE RISK MODEL FOR GREATER CAIRO

This paper describes an assessment methodology to estimate losses resulting from structural damage to the building population in Greater Cairo. The adopted framework is amenable to application in other regions that are typically characterised by low-to-moderate seismicity and where the inadequacy of data hampers the use of systematic and conventional seismic risk modelling approaches. Focus is firstly directed towards developing a ground shaking model. Towards this end, integrating data on the tectonic configuration, seismicity, and previous hazard studies for the region, is used to define the hazard. This is followed by collating data on geological structures and surface soil conditions, using a considerable number of boreholes, to produce a classification of different soil deposits. An inventory database for the existing building stock is then prepared. A general overview of the history of seismic provisions in Egyptian codes, combined with extensive ground surveys and satellite imagery, are used to delineate the area into geographical references of uniform building and soil characteristics. Using this information, the seismic vulnerability of the representative building models, designed according to prevalent codes and construction practices, is evaluated by carrying out extensive static nonlinear analyses. Use is made of capacity-spectrum methods for assessing the structural performance using a multi-level damage scale. Finally, the results are used to build-up an event-based loss model for possible earthquakes in the region