The Red Sea rift zone is an area of medium to high seismic hazard, with many
medium and large magnitude earthquake recorded historically and very
recently. On the other hand, the shoreline in South Sinai and on the Egyptian
mainland has undergone unprecedented development with tens of new minitowns
and tourist resorts. Detailed and verified seismic design criteria and
sample input motion have not been derived before this important area In this
paper, all available historical and instrumental records of earthquake activity
are reviewed, and a definitive catalogue assembled. Conventional probabilistic
seismic hazard analysis was undertaken, whilst ensuring the homogeneity of the
data used. Levels of ground motion for seismic design are derived as a function
of probability of being exceeded, and for different return periods. It is concluded
that a level of PGA of about 0.175g (rock-stiff sites) is a conservative value
recommended for design. Contrary to the recommendations of the Egyptian
seismic code, the levels of excitation for low-rise structures is significant and
should not be ignored. Moreover, the possible deterministic earthquake
scenarios for the area are discussed. These are used to select recorded groundmotion
accelerations from seismotectonic environments similar to the South
Sinai area. The average spectra from the selected suite of records is compared to
the ECS spectral model, and shown to be reasonable, though well below ECS in
the long period range. The conclusions and recommendations of this paper are
an important contribution to the study of seismic hazard and risk in an area not
elaborately studied before and is of interest to both practitioners and researches
who are concerned with earthquake issues in this part of the Middle East |
