Geoelectrical Characterization of the Peat Soil at Klias Peninsula, Beaufort, Sabah (Malaysia)

Electrical resistivity imaging (ERI) surveys were carried out at the Klias Forest Reserve, Beaufort, Sabah. The entire area consists of Crocker Formation and Quaternary deposits. The main purpose of the geophysical surveys was to characterize the properties of peat and measure the thickness of the peat soil. For this purpose, seven (7) traverses were established for electrical resistivity imaging (ERI) and induced polarization imaging (IPI). The configuration of the Schlumberger and Wenner array was applied by adopting 41 electrodes with 1.0m-5.0m electrode spacing. The length of the ERI IPI survey line varies from 80m- 200m. The core samples were collected at a depth of 0-6m. The resistivity survey lines R1, R2, R3, and R4 were conducted nearby Borehole A. Borehole B was taken alongside the survey line R5. Whereas Borehole C was taken near survey lines R6 and R7. The results of the ERI IPI surveys show that the subsurface strata are composed of peat materials with resistivity values of 15Ωm – 500 Ωm, clay having resistivity values of 30 Ωm – 60 Ωm and resistivity value of boundary between peat and marine clay resistivity range from 20 Ωm -80 Ωm. The thickness of the peat and clay obtained ranges from 0-6m and 6m-28m respectively. The clay layer is thickening towards the West to the East. While the peat layer shows a varied pattern from West to East. The combined approach between ERI, IPI and core sampling helped to better define the characterization of the material and their thicknesses within the subsurface.