Analysis of georadar responses on environmentally significant karst landform

Abstract

Peak-cluster depression (PCD) is a typical karst landform and a crucial aspect in non-invasive geophysical evaluation of the environmental concerns of the karst desertification regions (i.e., canopy growths, animal habitat, among others) related with karstification and its soil stocks and their moisture contents. To that end, a promising non-invasion, less labour-intensive and cost-prohibited geophysical technique (georadar/GPR) being limited in its operations because of the tilt signals and loss of information introduced by the uneven topography of PCD. Therefore, it requires a detailed investigation applying numerical analysis (considering karst topography and soil conductivity) implicating in a case study which is the scope of the present work. The findings of numerical analysis showed that under moderate soil conductivity conditions, the tilt signals could contain the reflections from both surrounding hills and subsurface inclined interfaces. The data processing workflows include the F-K filtering to remove or suppress the tilt signals. Then we applied the attribute analysis as additional information to aid in interpreting soil depth in depression. The soil depth obtained from the auger showed results highly consistent with that of the GPR findings. It is concluded that the application potential of GPR for the karst peak-cluster depression study is moderate to the fact that inferred information can partly be utilised while the rest is mixed or contaminated with other irrelevant information.