SEGJ Technical Conference


Analysis of time shift variations of GPR records from slight changes of soil water content


Abstract
Ground-penetrating radar (GPR) can detect the distribution of volumetric water content under the ground. However, the level of water table in standard soil structures is difficult to be measured by using GPR. We evaluate time-shift analysis for time-lapse GPR records with different distribution of water content. The reflection events from the transition zone of water content are sometimes difficult to detect on the survey sections of GPR and also on the survey section subtracted from two time-lapse records. However, time-shift analysis can detect events caused by shift of the transition zone depth. Upper events of the transition zone move to in shallower record time and lower events move to in deeper time when watertable moves to a shallower area. We demonstrate such characteristic phenomena using FDTD numerical simulations and discuss the analysis results applied for time-lapse records acquired in actual fields.