Field Experiments on a Square Hole-Type Metamaterial: Exploring the Attenuation of Rayleigh and Love Waves

Seismic metamaterials (SMs) have gained significant attention for their ability to reduce seismic wave energy. However, the majority of research on SMs has been dominated by numerical simulations, with relatively few field experiments validating their effectiveness. Additionally, the focus has been primarily on attenuating Rayleigh waves, with less attention given to Love waves. In this study, We first designed a seismic metamaterial featuring a periodic and symmetric array of square holes using numerical simulations as our research platform. We then explored its attenuation effects on Rayleigh waves, particularly Love waves, through field experiments. The results revealed not only differences in energy attenuation between these wave types but, more importantly, uncovered a phenomenon we termed Bandgap-Induced Attenuation Mode Inversion within the ultra-broadband gap generated by SMs, where Love waves exhibited greater attenuation than Rayleigh waves below 50 Hz, while Rayleigh waves exhibited greater attenuation above 50 Hz. These findings highlight the necessity of considering both wave types when designing cost-effective seismic metamaterials, providing valuable insights for the development and application of metamaterials that can effectively mitigate the energy of different seismic wave modes.