Application of 2-D Resistivity Imaging and Seismic Refraction Method in Identifying the Structural Geological Contact of Sedimentary Lithologies

Abstract

The interest of this study was to prove the existence of geological contact to field models with presences of outcrops as references. The physical relief of the outcrops can be determined by geological events of faulting, fracture, and folding. Geological contact plays important roles in environmental studies. 2-D resistivity imaging is the best method used for identifying the geological structures of study area located in Guar Jentik, Perlis and Bukit Kukus, Kedah. Besides that, seismic refraction method also applied at the study area. Results from both methods were integrated to get data correlation. There is good correlation produced which have successfully proved the existence of the faults and contact zones in study areas. Resistivity result shows that first study area has two main zones, red mudstone with resistivity value of 1 Ωm – 100 Ωm, sandstone with resistivity value of 2000 Ωm – 9000 Ωm, and Seismic refraction has provided the result on velocity of each zone, mudstone zone is 200 m/s -1800 m/s and sandstone zone is >2000 m/s. The geological contact of fault is determined between the red mudstone zone and sandstone zone. In the second study area, the fracture was found within chert zone and contact zone is located between the chert zone and mudstone zone. In addition, the fold is found to form in the chert zone. Mudstone zone has resistivity value of 1 Ωm – 1500 m/s and chert zone has resistivity value of 2600 Ωm – 35000 Ωm. The first layer of the seismic section is consisting of mudstone with a velocity of <800 m/s and the velocity obtained for the second layer was generally >1200 m/s is interpreted as chert zones.