Frequency dependence of seismic dissipation in saturated rocks

Measurements of the specific dissipation factor, Q⁻¹, have been made in saturated rock as a function of effective pressure. The measurements were made at two different frequencies, one in the range of 100 to 250 Hz and the other in the range of 7 to 9 kHz, using the resonant bar method. In saturated rock, Q⁻¹ is lower at the lower frequency, and the difference between the values of Q⁻¹ measured at the high and low frequencies decreases as effective pressure increases. At effective pressures greater than 200 bars, the Q⁻¹ of saturated Berea sandstone measured at 200 Hz approaches that of dry Berea sandstone measured at 7 kHz.