Nonlinear Site Response Analysis In District Xiii, Budapest

Urban seismic hazard assessments must account for local soil conditions that can significantly alter ground motion characteristics. This study presents a nonlinear one-dimensional (1D) site response analysis for four locations within Budapest’s District XIII—an area characterized by Quaternary Danube sediments underlain by Tertiary clays. The characterization of the seismic subsurface was performed using a multichannel analysis of surface waves (MASW) and seismic cone penetration tests (SCPT) that provided detailed shear wave velocity (V_s) profiles. These profiles were used in nonlinear simulations, including seven spectrum-matched ground motion records.

The results demonstrate a pronounced site amplification effect, particularly in the short-period range (0.2–0.4 seconds), which aligns with the natural periods of low-to-midrise buildings typical of the district. Notable inter-site variability was observed, which was influenced by differences in soil stiffness and stratigraphy, with peak amplification factors reaching up to 2.6. The results provide a valuable guideline to formulate the new Hungarian National Annex of Eurocode 8.