Perfect Seismic Wave Absorbers for the 8th Magnitude Earthquakes

Abstract

Most modern buildings and infrastructures are not designed to resist 8th magnitude earthquakes, for which studies on phononic crystals and local resonators reported so far are not particularly suited. We report a type of all-metallic decorated membrane resonators as deep subwavelength vibration dampers, which are modeled as meta-soil, that can block and even totally absorb underground seismic waves up to 8th magnitude earthquakes. Transmission attenuation exceeding 20 dB and absorption up to 98 % are numerically demonstrated for 1 Hz Rayleigh waves by a dozen rows of vertical underground wells filled with the meta-soil. A scaling law in the same form as the mass density law for airborne acoustic waves has been analytically derived and numerically verified.