UC Irvine

It is known that earthquake and seismic activities changes behavior of a hydrological system. These changes are attributed to changes in permeability of the medium due to pore pressure oscillations induced by seismic waves. Multiple studies suggest that fine particle mobiliza- tion inside fractures due to these oscillation, may be the possible mechanism that enhances permeability; however, direct evidence is lacking. Here I introduce a set of experiments to further analyze e ects of pore pressure oscillations on fine particle mobilization inside a transparent analog fracture. I performed a controlled perturbation, using the designed oscillator, with peak flow rate of 1.9 ml/min and frequency of 1 Hz for 5 minutes. E ective aperture or hydraulic aperture is widely used in aperture studies to represent permeability of a fracture. In this study I observed that e ective aperture enhanced by pore pressure oscillations from 58.77 μm to 73.23 μm. This enhancement was correlated to the particles that were mobilized during the oscillations. The particle mobilization was also visible in the animation created from the images that were taken during the experiment.