LAUSR

Each year, on average, a magnitude-8 earthquake strikes somewhere in the world. In addition, 10,000 earthquake related deaths occur annually, where collapsing buildings claim most lives. Moreover, in recent events, industry activity of wastewater reinjection is suspected to cause earthquake swarms that threaten high-value infrastructure and properties. Earthquake engineering technology has evolved over many years to minimize the destructive effects of seismic waves. However, even under the best practices, significant damage and fatalities can still occur. Here we present a novel concept that redirects and attenuates hazardous seismic waves using an engineered subsurface seismic barrier. The barrier consists of borehole array and trench complexes that inhibit destructive seismic waves from entering a designated ‘protection zone’. The barrier is designed to counter not only surface waves in the aerial-horizontal plane, but employs a vertical ‘V’ shaped muffler structure composed of opposing boreholes or trenches to mitigate seismic waves from diffracting and traveling in the vertical plane. Computational seismic wave propagation models suggest that air or fluid filled subsurface Vshaped muffler structures are critical to the redirection and self-interference of broadband hazardous seismic waves in the vicinity of the structure to protect. The computational models are compared with experimental data obtained from large bench-sized models containing borehole arrays and trenches. The computer models and bench scale measurements indicate that effects of a devastating 7.0 Mw -magnitude earthquake can be attenuated to those of a minor magnitude-4.5 or -5.5 Mw earthquake within a specified protection zone.