Laboratory Simulation of the Influence of Earth Stress Changes on Wave Velocities
Rune M. Holt, Erling Fjær, Anne-Kari Furre, 1996. "Laboratory Simulation of the Influence of Earth Stress Changes on Wave Velocities", Seismic Anisotropy, Erling Fjær, Rune M. Holt, Jaswant S. Rathore
Download citation file:
Synthetic sandstones have been manufactured under controlled stress conditions. The velocities of P- and S-waves were measured in two orthogonal directions, permitting studies of effects of cementation, compaction, unloading and reloading on velocities. Assuming that the samples and the experimental procedures are representative for earth materials and earth stress changes, these effects may be related to processes like lithification, burial / fluid withdrawal, uplift / coring, and burial after uplift / core testing under stress. The results show that unloading leads to largely reduced velocities, and also to a velocity anisotropy associated with the initial stress anisotropy. Strong stress dependency is prominent in materials which have been previously unloaded, indicating that laboratory measured stress dependency may often be a result of the unloading while coring.