Experimental measurements for a seismic landmine detection system

Experimental and numerical models have been utilized at Georgia Tech in the research and development of a seismic landmine detection technique which generates seismic waves in the soil using a surface-coupled electrodynamic transducer and detects normal surface displacements with a non-contact radar sensor. As the numerical models have shown a strong dependence upon material properties of the soil as a function of depth, experiments have been conducted at six field sites and in the experimental model to quantify the effect of different soil conditions upon the operation of the seismic landmine detection system and to measure depth-dependent material proper-ties. Measurements have been made with and without buried anti-personnel and anti-tank mines to determine the effects that landmines have upon the propagation of seismic waves. Surface waves have been measured using the non-contact radar sensor as well as triaxial accelerometers and geophones. Post-processing has included the examination of particle motion in three dimensions, the identification of individual wave types through polarity tracking and dispersion curves, and the extraction of individual propagating waves. The field sites include wet and dry sand at a beach, a roadbed at a U. S. Government facility in a temperate climate, frozen ground, clayey soil with and without rocks, and a silt-sand mixture in a coastal region.