Laboratory Evidence of Transient Pressure Surge in a Fluid-Filled Fracture as a Potential Driver of Remote Dynamic Earthquake Triggering

Abstract Seismic waves carrying tiny perturbing stresses can trigger earthquakes in geothermal and volcanic regions. The underlying cause of this dynamic triggering is still not well understood. One leading hypothesis that a sudden increase the fluid-pore pressure fault zone involved, but exact physical mechanism unclear. Here, we report experimental evidence which fluid-filled fracture was shown to be able amplify an incoming seismic wave. We built miniature sensors directly placed them inside thin measure fluid during wave propagation. By varying aperture from 0.2 9.2 mm sweeping frequency 12 70 Hz, observed lab could amplified up 25.2 times compared with incident-wave amplitude. Because reduce effective normal stress allow slide, our transient surge phenomenon may provide for earthquake triggering.