Nonlinear Subsoil Seismic Response in Boumerdes: Toward Seismic Microzonation and Urban Planning Support

The accurate estimation of earthquake-induced ground motion at a specific site is crucial for evaluating seismic hazards, including soil deformation, ground failure, and potential structural damage. This study investigates the seismic response of subsurface soil profiles in the Boumerdes region (Algeria) using numerical site response analysis. The assessment focuses on Peak Ground Acceleration (PGA) and response spectra while accounting for soil nonlinearity through both equivalent-linear and fully nonlinear approaches. The input motion corresponds to the ground excitation recorded during the Boumerdes earthquake of May 21, 2003. The results reveal significant variations in surface ground motion, characterized by amplification or attenuation relative to the bedrock input motion, highlighting the strong influence of local site effects. These findings contribute to a better understanding of seismic wave propagation in local soil conditions and provide a scientific basis for site-specific seismic microzonation of Boumerdes, supporting improved seismic risk mitigation and resilient urban planning in this seismically active region. These findings are also relevant to urbanized areas, where land-use choices require site-specific seismic information.