Space Phys Research Articles

Transient streaming potential measurements on fluid-saturated porous structures: An experimental verification of Biot’s slow wave in the quasi-static limit

The time behavior of the streaming potential is identical to that of differential fluid pressure when local laminar flow is maintained and electromagnetic relaxation is not important. The time evolution of the streaming potential waveform resulting from the application of a pressure pulse to one face of a cylindrical water-saturated porous structure is found to depend on the elastic properties of the fluid and rock frame and on the porosity and permeability of the core. The analysis of this quasi-static flow based on Biot’s soil consolidation work [Biot, J. Appl. Phys. 12, 155 (1941)] and advanced by J.R. Rice and M.P. Cleary [Rev. Geophys. Space Phys. 14, 227 (1976)] is completely equivalent to that obtained from Biot’s slow wave model [M.A. Biot, J. Acoust. Soc. Am. 28, 168 (1956)] in the limit of zero frequency. Both analyses result in a homogeneous diffusion equation in pore pressure (and streaming potential) where the diffusivity is expressed in terms of the bulk moduli of the fluid and solid constituents, bulk and shear moduli of the solid frame, fluid viscosity, porosity, and permeability. The predicted streaming potential transient response is in excellent agreement with experimental observations, permitting, for example, the extraction of sample permeability. Models assuming an incompressible frame are shown to be grossly inadequate in describing the temporal features of quasi-static flow.

A comparison of atmospheric acoustic sounder configurations versus meteorological conditions

The relationship of atmospheric data gathered from three-axis bistatic sounders operating at 1, 2, and 4 kHz, and a 2-kHz three-axis monostatic sounder is presented. Wind profiles are computed using the complex covariance function of the returned signal to estimate the power spectrum mean frequency. The backscatter data are presented as high quality grey scale and pseudocolor temperature structure. The data were gathered over varied terrain from Texas to Alaska and represent a sample of common and unique planetary boundary layer events including: ground radiation inversions; elevated subsidence inversions showing shear and convection stresses; gravity wave trains; and convection cells correlated with vertical winds. Several unique events are presented including an isolated large amplitude gravity wave (>600 m) associated with a frontal passage and a radiation inversion with an associated low level jet producing extreme low level shear (≈12 m s-1/150 m). The computational techniques and the associated geometry and frequency are compared to a previously published overview [E. H. Brown and F. H. Hall, Jr., Rev. Geophys. Space Phys. 16, (1) 47–110].

Brittle phenomena : Logan, J M Revs Geophys Space Phys, V17, N6, Sept 1979, P1121–1132

Brittle phenomena : Logan, J M Revs Geophys Space Phys, V17, N6, Sept 1979, P1121–1132

804045 Recent advances in rock magnetism : Day, R Revs Geophys Space Phys, V17, N2, April 1979, P249–256

804045 Recent advances in rock magnetism : Day, R Revs Geophys Space Phys, V17, N2, April 1979, P249–256

High temperature deformation of rocks and minerals : Tullis, J A Revs Geophys Space Phys, V17, N6, Sept 1979, P1137–1154

High temperature deformation of rocks and minerals : Tullis, J A Revs Geophys Space Phys, V17, N6, Sept 1979, P1137–1154

Pore pressure effects in crustal processes : Martin, R J Revs Geophys Space Phys, V17, N6, Sept 1979, P1132–1137

Pore pressure effects in crustal processes : Martin, R J Revs Geophys Space Phys, V17, N6, Sept 1979, P1132–1137

804076 Review of plate tectonics : Burke, K; Sengor, A M C Revs Geophys Space Phys, V17, N6, Sept 1979, P1081–1090

804076 Review of plate tectonics : Burke, K; Sengor, A M C Revs Geophys Space Phys, V17, N6, Sept 1979, P1081–1090

Steady state flow of rocks : Carter, N L Rev Geophys Space Phys, V14, N3, Aug 1976, P301–360

Steady state flow of rocks : Carter, N L Rev Geophys Space Phys, V14, N3, Aug 1976, P301–360