Differential Effects of Soil-Structure Interaction on Seismometer Recordings

China is situated in a seismically active zone, necessitating urgent improvements in earthquake disaster prevention and mitigation capabilities. To address the distortion of seismic motion recordings caused by soil-structure interaction (SSI) in low-rise residential buildings equipped with seismometers, this study establishes an integrated finite element model of a soft soil site, shallow foundation, and three-story reinforced concrete frame structure based on seismometer deployment characteristics in the Ya'an region. Four real seismic ground motion records were selected for numerical simulations of vertically incident SV waves, comparing acceleration response differences between structural monitoring points and free-field surface conditions. Key findings include:(1) Acceleration peaks at structural foundations and lower-story wall monitoring points show minimal differences but significant deviations from free-field recordings, with masonry infill walls dominating low-story acceleration distribution;(2) SSI-induced amplification/attenuation effects on structural acceleration responses are modulated by seismic spectral characteristics, showing 1.25× amplification in the structural natural frequency range (0.2–0.6 s) and high-frequency attenuation (>15 Hz) due to soil filtering;(3) Acceleration response spectra exhibit notable enhancement within the structural characteristic period range (0.2–0.6 s), indicating selective amplification of short-period seismic motions by residential buildings;(4) Site flexibility exacerbates high-frequency filtering, while instrumental intensity deviations primarily arise from coupled seismic motion characteristics, structural parameters, and site conditions, with SSI alone contributing minimally to intensity assessment. These results provide theoretical foundations for optimizing seismometer deployment and revising earthquake early warning systems.