Frequency-dependent seismic properties of cracked and fluid-saturated crustal rocks: a systematic laboratory study

Fluid saturation of the cracked rocks of the Earth's upper crust is a major determinant of its mechanical behaviour and chemical evolution. Fluids play a vital role in the earthquake cycle, the formation of ore deposits, the extraction of oil and gas, natural and hot-dry-rock geothermal systems, and waste disposal. Fluids are predicted to exert a diagnostic, strongly frequency-dependent influence on seismic wave speeds and attenuation in cracked crystalline rocks - but this remains largely untested experimentally. We seek to rectify that situation through the systematic application of newly developed methods for laboratory measurements on fluid-saturated rocks at seismic frequencies.