The seismic signature of crustal fluids

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 by developing and testing new capability for laboratory measurements on fluid-saturated rocks at seismic frequencies.