Forensic Assessment on Near Surface Landslide Using Electrical Resistivity Imaging (ERI) at Kenyir Lake Area in Terengganu, Malaysia

Electrical resistivity method which was championed by geophysicist has increasingly popular in civil engineering application due to its efficiency in term of cost, time and data coverage. This study performed with particular reference to electrical resistivity imaging (ERI) in evaluating the slope failure at Kenyir Lake, Malaysia. During the data acquisition, two lines of ERI was performed using ABEM Terrameter LS set of equipment based on Schlumberger array. Moreover, electrical resistivity anomaly was managed to detect the presence of geological structure with particular reference to fault and rock discontinuities which associated to low resistivity anomaly. The heterogeneous of the subsurface material presented using integrated analysis of ERI and borehole data enabled forensic assessment of the landslide. The combination of heavy rainfall and existing geological structure (weakness zone) was believed to be a major factor which triggered this failed slope. This result was applicable to assist the geotechnical engineer in design concept recommendation of the slope remediation with fast, less cost and wide data coverage. Finally, ERI results with borehole verification was applicable to be adopted in landslide forensic assessment based on slope geomaterials stiffness variations generated after the slope movement.