ERSC 3V93 Lecture 52: Seismic Methods v2 IV
6 May 2016
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Document Summary
Gpr used extensively for geologic studies of coarse-grained deposits coastal, fluvial, deltaic and glacial deposits. Gpr surveys can be conducted on fresh-water lakes provided conductivity is low (freshwater) collect data on ice or place antennas in rubber boat. Not affected by weeds or gasified sediments main advantage, over acoustic methods. Imaging of coastal dunes, beach ridges map out individual cross-strata. Gpr used increasingly in forensics to locate unmarked graves indicated by diffraction events or loss of reflector continuity. Detectable targets: change in soil conductivity decomposing tissues air voids spaces (casket, soil voids) thoracic cavities (air space), skull, tissues clothing. Decomposition of body changes soil chemistry ions alter soil conductivity and permittivity, high. Detection of buried cables and utilities metallic objects show up as high amplitude negative polarity diffractions. Also detect pvc and concrete pipes and other materials such as wood low amplitude diffraction and reflection events when compared to metal targets positive amplitude.
