Evidence for HV peaks superposition leading to extreme horizontal ground motion amplification revealed by the Xochimilco ambient noise tomography

Researchers have uncovered extreme horizontal ground motion amplification in Mexico City's Xochimilco region, attributed to the superposition of multiple resonance peaks. This phenomenon, revealed through ambient seismic noise tomography combining horizontal-to-vertical spectral ratios (HVSR) and multimodal dispersion curves, highlights the complex interaction between sedimentary layers with varying water content and lava intrusions. The study, involving 84 seismic stations, demonstrates that while surface wave energy is distributed across fundamental and higher modes, the spatially continuous decrease in dominant peak frequency toward the lake interior masks heterogeneous amplification patterns. These findings are crucial for seismic mitigation strategies in Mexico City and may apply to other cities built on sedimentary basins.

Ramos Avila, V., Perton, M., & Aguirre, J. (2025). Evidence for HV peaks superposition leading to extreme horizontal ground motion amplification revealed by the Xochimilco ambient noise tomography. Geophysical Journal International, 241(3), 1988–2002. https://doi.org/10.1093/gji/ggaf139