Prediction and validation of soil electromagnetic characteristics for application in landmine detection

摘要

Factors controlling the distribution and intensity of soil magnetic susceptibility (MS) and electrical conductivity (EC) were investigated. The purpose was to determine the factors to be considered in predicting MS and EC characteristics of soils in landmine-affected areas and in developing effective landmine detection systems and strategies. Results indicate that knowledge of bedrock geology, soil weathering and transportation (wind and water) history is essential to predict soil MS and EC characteristics. These factors determine the distribution, concentration and mineral type (e.g., ferromagnetic and clay minerals) in soil. For example, fluctuating water tables in tropical climates could produce soils rich in ferromagnetic minerals at the surface, even though their source (bedrock) may have low iron content. Also, subsequent weathering may change these minerals to high or low MS values. Although high clay concentrations homogeneously distributed may not produce high soil EC values, a low clay content concentrated in a single layer may produce extremely high EC values. These suggest that bedrock geology, agricultural soil, air photo and airborne geophysical survey maps can be used for predicting soil MS and EC characteristics of landmine-affected areas. Laboratory and surficial geophysical surveys are techniques for use in validation.