Seismic Cloaking Protection from Earthquakes

Each year, large ground motions from earthquakes cause infrastructure damage and loss of life worldwide. Here we present a novel concept that redirects and attenuates hazardous seismic waves using an engineered seismic-muffler acting as a cloaking device. The device employs vertically-oriented, sloping-opposing boreholes or trenches to form muffler walls and is designed to: 1) reflect and divert large amplitude surface waves as a barrier, while 2) dissipating body and converted waves traveling from depth upward into the muffler duct. Seismic wave propagation models suggest that a seismic-muffler can effectively reduce broadband ground motion directly above the muffler. 3D simulations are also compared for validation with experimental data obtained from bench-scale blocks containing machined borehole arrays and trenches. Computer models are then scaled to an earth-sized model. Results suggest a devastating seismic energy magnitude 7.0-$\mathrm {M}_{\mathrm {E}}$ earthquake can be reduced to less damaging magnitudes experienced in the muffler vicinity, 4.5- $\mathrm {M}_{\mathrm {E}}$ (surface wave) and 5.7- $\mathrm {M}_{\mathrm {E}}$ (upgoing coupling into the muffler). Our findings imply that seismic-muffler structures significantly reduce the impact of the peak ground velocity of dangerous surface waves, while, seismic transmission upward through the muffler base at depth has marginal effects.