A generalized GPR application potential zonation in the karst catchment of SW China

Abstract

Abstract The epikarst together with its soil stocks (subcutaneous structure), resulted from the dissolution and weathering of soft rocks, are crucial to the fact that they may contribute to the canopy growth and can significantly influence the ecological restoration and organic carbon sequestration. For the delineation of these ecological significant karst features, ground penetrating radar (GPR) seemed to be a promising technique because of its noninvasive, cost-prohibited and lesser labor-intensive operations. However, the landscape heterogeneity, connection between surface morphology and underground environments and high vegetative endemism making karst as a complicated environment for any geophysical application. Same is the case with the GPR applicability in SW Chinese catchment as it is affected by numerous features such as epikarst slope, peak-cluster depression, tree trunks and roots, precipitation and moisture contents as well as proximity to high voltage power lines. Considering these factors, the present study analyzes the GPR data acquired at the sites representing each of these aforementioned features. The analysis includes calculation of GPR attributes as average energy, coherence and total energy together with the forward calculations wherever required. Tilt signals from surrounding hills mix with the tilt signals from subsurface inclined interfaces in a GPR image. The information of soil-rock distribution above epikarst in the slope is difficult to obtain completely for GPR. The interpretation of epikarst bottom boundary faces two possibilities considering the affects of moisture. The affects of tree trunks and roots and strong electromagnetic fields of high voltages lines make the GPR data interpretation about subsurface soil-rock structure high difficult. The soil moisture greater than ~ 30% makes GPR inapplicability. These site-specific findings are used for the generalized GPR application potential zonation in the typical SW Chinese catchment (the central Guizhou plateau). The findings of the present study may prove as a reconnaissance and an application paradigm for the future GPR utilities in complex karst characterization especially, in SW China as well as the areas having similar karstic conditions.