The newly generated cities inside Egypt are in greet need for the assessment of engineering problems and natural hazards. New Cairo City is one of the biggest urban areas that have huge amount of investments now. Seismic hazard assessment is used to identifying the amount of shaking that may reach New Cairo City area and the new construction may suffer from. A modified and updated earthquake catalogue till 2003, for earthquakes occurring in Egypt and surrounding areas is used for estimation of recurrence relationships and regression constants. Maximum magnitude earthquake was calculated for 72 source zones used in the present study to evaluate the amount of risk at the New Cairo city area. These data were used to generate Peak Ground Acceleration (PGA) contour maps based on the regionally developed PGA attenuation relations for all shallow seismic sources for respective forecast time periods (exposure times) 25 and 50 years. Hazard maps were calculated using the computer program developed by McGuire. One of the biggest engineering problems that constitutes a potential hazard is the clay and marl intercalations exist in the area. The clay is considered as a dangerous unwanted layer in some formations because of its engineering problems and unrealistic amount of swilling especially in the area of study. To detect and trace this unwanted layer a total of 23 seismic refraction profiles are conducted using three shots for each profile. GRM is used to interpret the acquired data, the resulted depth sections are verified by advanced Finite Difference (FD) technique. Moreover samples were taken as possible from this clays to investigate its swelling. A final map for best safe locations from geophysical point of view is constructed.
Bibliographical notePublisher Copyright:
© 2004 Society of Exploration Geophysicists.
ASJC Scopus subject areas
- Geotechnical Engineering and Engineering Geology