Soil characterization and process monitoring in small-scale tests such as 1g models, shake table and centrifuge models can be effectively conducted with complementary elastic and electromagnetic waves. Small changes in P-wave impedance permit developing Pwave reflection imaging. Its implementation using ultrasound in small-scale soil models is attained by optimizing the operating frequency and selecting the proper transducers. The technique permits detecting layers and inclusions in submerged soils with submillimeter resolution. S-wave velocity depends on the shear stiffness of the skeleton. Shear wave propagation gains particular relevance in the characterization of uncemented soils where stiffness is stress dependent. Bender elements are excellent transducers for S-waves due to their outstanding soil-transducer coupling and their high frequency response. The installation can be designed to gather tomographic data. The electrical conductivity of a soil depends on the conductivity of the pore fluid, porosity and the soil specific surface. High-resolution electrical resistivity profiles are determined using an electrical needle probe. These profiles provide detailed information regarding the spatial variability of the soil mass with millimeter resolution. Resistivity measurements are extended to noninvasive electrical resistance tomography to produce images that correlate to density distribution, contaminant concentration, and/or anomaly detection.