Multi-fold GPR study of shallow structure and stratigraphy of unconsolidated sediments and rocks

In this study we apply multi-fold (MF) techniques to imag,e and characterize layered sediments and rocks. We exploit macro-model dependent and independent imaging methods to achieve enhanced imaging. Depth converted time-domain RMS velocity maps and V-Z macro models provide further information about physical properties of the sediments and rocks and are used to characterize the sedimentary sequence and extract geological information from radar stratigraphy. Gravel and sand deposits in paleochannels are effectively identified and characterized by MF methods due to the sensitivity of such methods to velocity variations associated with porosity and water content. The velocity difference between silt loams and gravellsand deposits is an effective indicator and allows imaging of tlhe paleochannels limits as well as identification of filling deposits. Velocity models obtained by different techniques (prestack depth migration velocity analysis, CRS based velocities) provide further quantitative indications on water content.