Storativity from Seismic Waves: Using Rayliegh Waves for Seismic Efficiency Calculations

Storativity is an important input in aquifer modeling for understanding the potential volume of water that an aquifer can contain. A Seismic Efficiency method for calculating estimates of specific storage has been developed for confined aquifers using the pressure fluctuation in wells measured from the Rayleigh waves of naturally occurring seismic events. Similar to estimates of specific storage from changes in barometric or tidal pressures, the Seismic Efficiency method relates the change in water pressure to the pressure exerted on the aquifer matrix by passing Rayleigh waves. Results from the Seismic Efficiency method compare favorably to results from Barometric Efficiency estimates of specific storage, with the advantage that Seismic Efficiency calculations require a much shorter time period of data collection than Barometric Efficiency or Tidal Efficiency calculations. Seismic Efficiency calculations have been applied to a heterogeneous aquifer system, and have shown how data from one seismic event can be used to show variability of specific storage within that system. As models become more necessary for planning aquifer management practices, the need for complete data sets also becomes more necessary. The Seismic Efficiency method has been proven to be another useful tool in providing data for a storativity data set and ultimately improving model outputs.