Seismic site amplification in multilayer soil under obliquely incident SH waves

2-D seismic site amplification of obliquely propagating anti-plane motions in viscoelastic soil models is presented for two case studies. First, results issued from the application of recursive filters for discrete-time analysis of site amplification under non-vertical wave incidence to the analytical soil layer model of El-Asnam Cultural Center site (North-Western Algeria), are compared to exact solutions from the discrete-frequency approach. In a second stage, seismic site amplification in a multilayer viscoelastic soil profile model of the “500 Residential Apartments” site in the El–Asnam region, under obliquely incident SH waves, is analyzed in detail, using the Thomson-Haskell technique modified to account for both internal and radiation forms of damping. Results of sensitivity analyses performed in an attempt to estimate seismic site amplification of soil surface acceleration time histories under bedrock and rock outcropping input motions, as affected by angle of incidence variations and rock to soil impedance ratios, are discussed. •2D seismic amplification in multilayer soil under incident SH waves is investigated.•A discrete time wave propagation for 2D seismic site amplification is discussed.•Both bedrock and rock outcropping cases are examined based on a real case study.•Two major issues: specification of input motion and damping effects are examined.•Incident angles affect input and surface motions and both spectral shifts and peaks.