Tropical Peat GPR & ERI

GPR and ERI Profiles of Tropical Peatland Penetrating to 4 m and 9 m Depth, Respectively.

Fig. a. GPR profile of peat collected using a 100 MHz antenna at Site TG2 in West Kalimantan, Indonesia. Stratigraphy in several peat cores is shown. White arrows indicate significant diffraction hyperbolas interpreted as woody debris. GPR event at 0.8 m is the confirmed water table. Results confirm that peat base can be picked in GPR profiles with cm accuracy.

Fig. b. ERI subsurface resistivity collected with 1-m electrode spacing on the GPR transect. ERI shows a resistive upper layer, confirmed peat, underlain by a conductive layer, confirmed clay. Black dots represent the contact between peat and underlying clay. This contact was picked in the resistivity image using the average of resistivity values that coincide with the peat-clay contact in the cores.  Note lateral variations in deeper mineral soil resistivity. ERI provides a low resolution estimate of peat base depth and information about lateral variations in peat and sub-peat stratigraphy.*

* Comas, X., Terry, N., Slater, L., Warren, M., Kolka, R., Kristiyono, A., Sudiana, N., Nurjaman, D., and Darusman, T., 2015, Imaging tropical peatlands in Indonesia using ground-penetrating radar (GPR) and electrical resistivity imaging (ERI): implications for carbon stock estimates and peat soil characterization: Biogeosciences, v. 12, no. 10, p. 2995-3007.