Using Laboratory Measurements of Electrical and Mechanical Properties to Assist Interpretation of Field Data from Shallow Geophysical Measurements

Abstract

Reconstruction of shallow subsurface structure from geophysical data is a central problem for many environmental and engineering applications. We observe that for shallow soil distributions, seismic data alone or electrical data alone may provide a good reconstruction of the subsurface. We show that using joint seismic and electrical data will improve the reconstruction of shallow structure. Our results emphasize that the availability of techniques for making laboratory measurements of ultrasonic velocities at low pressures in unconsolidated materials and the ability to measure complex impedance in similar samples are key elements of this approach.

A Survey of Department of Energy–Sponsored Geophysical Research for Shallow Waste Site Characterization

“…These approaches enhance the determination of key vadose zone subsurface properties such as moisture content and capillary pressures, as well as saturated hydraulic conductivity. Integrating seismic measurements with electrical data and hydrological properties may also improve the capability to determine soil porosity, composition, and fluid distributions (Bertete‐Aguirre et al, 2002; Berryman et al, 2000).…”

“…Researchers compared their measurements to theoretical models, other laboratory measurements from literature, and available field data and investigated the role of microstructure, fluid and clay distribution, and chemical effects on measured geophysical properties. The researchers have developed and tested algorithms to relate measured geophysical properties to porosity, soil composition, and fluid distribution (Bertete‐Aguirre et al, 2002; Berryman et al, 2000).…”

Seismic Velocities Contain Information about Depth, Lithology, Fluid Content, and Microstructure

“…Generally the data in the literature have been interpreted for first-order structural features such as using surface wave methods to find subsurface cavities, using reflection techniques to find the water table or faults, and using refraction techniques to find variations in lithology that manifest as variations in velocity structure. New laboratory measurements of ultrasonic velocities in soils at low pressures (e.g., Bonner et al, 2001;Zimmer et al, 2001) point the way for developing next-generation interpretation methods (e.g., Bertete-Aguirre and Bertete-Aguirre et al, 2002) that may allow seismologists to obtain more information from their data in the future.…”