Soil geotechnical characteristics for seismic risk mitigation at the southern extension of Marsa Alam city, Egypt

ABSTRACT The seismic hazard assessment for mitigating the seismic risk is an essential step before starting construction of a new settlement. One of the tools that could help in achieving this goal is the application of seismic refraction method for evaluating the geotechnical characteristics and dynamic properties of the soil deposits. Dynamic characteristics are fundamental for understanding the response of the soil under dynamic loading. Shallow refraction technique is in-situ test depends on the computation of seismic wave velocities which penetrating the soil. A total number of 88 compressional (P) and Shear wave (S) seismic refraction profiles have been conducted at the southern extension of Marsa Alam city on the Red Sea coast. The average P- and S-wave velocities were estimated for the subsurface layers consequently. Microzonation map for each layer was released by the spatial interpolation of data. In addition, the iso-thickness map was created for manifesting the soil thickness all over the studied area. Geotechnical parameters of the subsurface sediments were computed, as well as the zonation maps for density and N-value parameters have been created. The obtained maps emphasize that the first layer could be considered as foundation soil due to it is relatively stiffness