Reference-based measurement of stress-dependent ultrasonic velocity and seismic quality factor

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Abstract

We report ultrasonic laboratory measurements of P-wave velocity and quality factor (Q) in a sandstone sample under stepwise uniaxial loading (0–90 kN). Full ultrasonic waveforms were recorded at each load increment. Because Q estimation is more sensitive than velocity to coupling conditions, instrumental response, and spectral processing, particular emphasis was placed on amplitude-consistent acquisition and reference-based attenuation analysis. An aluminum specimen of identical geometry was measured under the same protocol to characterize system-related attenuation and to enable spectral-ratio-based estimation of effective Q relative to a high-Q reference. The sandstone exhibits pronounced stress dependence in both velocity and Q, indicating path-dependent anelastic dissipation associated with microcrack closure and frictional grain-contact losses.