Integration of Seismic Refraction and 2D Electrical Resistivity in Locating Geological Contact

Nisa’ Ali, Rosli Saad, M. M. Nordiana

Geophysics Section, School of Physics, Universiti Sains Malaysia, Penang, Malaysia.

DOI: 10.4236/ojg.2013.32B002                

Abstract

The aim of this research is to locate the geological contact for engineering purpose applying seismic refraction and 2D electrical resistivity method. Resistivity and seismic refraction method was conducted on four survey lines with 3 lines running from NW to SE which about parallel to each other and 40 m apart while the fourth line was running from SW to NE. The 2D resistivity survey used minimum electrode spacing of 5 m and the survey used pole-dipole array with minimum current was 2 mA and maximum was 20 mA. The seismic refraction survey used 5 m geophone spacing with offset shot was + 30 m and - 30 m. Resistivity results generally show the area was divided into two main zones, alluvium with resistivity value of 10 - 800 ohm-m, and granite bedrock with resistivity value of > 2500 ohm-m. There is a geological contact between granite and alluvium. The seismic results show the area consists of two layers. The first layer (top layer) with velocity of 460 - 900 m/s which was alluvium mixed with boulders. The second layer with velocity of 2060 - 3140 m/s with depth 71 - 90 MSL. The thickness of the overburden is 5 - 15 m.

Keywords

Geological Contact; 2D Electrical Resistivity; Seismic Refraction

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	R. C. Howe, “Geologic Contacts,” Journal of Geoscience Education, Vol. 45, 1997, pp. 133-136.
[2]	G. H. Davis, “Structural Geology of Rocks and Regions,” John Wiley & Sons, Inc., 1984, p. 492.
[3]	R. Saad, M. M. Nordiana and Edy Tonnizam Mohamad, “The 2D Electrical Resistivity Tomography (ERT) Study for Civil and Geotechnical Engineering Purposes,” Electronic Journal of Geotechnical Engineering, Bund, Vol. 16, 2011.
[4]	F. W. Roe, “The Geology and Mineral Resources of The Neighbourhood of Kuala Selangor and Rasa, Selangor, Federation of Malaya, with an Account of The Geology of Batu Arang Coal-Field,” Geological Survey Department Federation of Malaya, 1953.
[5]	R. Saad, “Novel Protocol of Engineering Geophysics In Urban Environments,” Ph.D. Thesis, University Sains Malaysia, 2009.
[6]	R. L. Sengbush, “Seismic Exploration Methods,” IHRDC Publishers, 1983. doi:10.1007/978-94-011-6397-2
[7]	D. H. Griffiths and R. F. King, “Applied Geophysics for Geologists and Engineers: The Elements of Geophysical J Prospecting,” Pergamon Press, 1981.
[8]	J. M. Reynolds, “An Introduction to Applied and Environmental Geophysics,” John Wiley & Sons, Ltd., 1997, p. 796.
[9]	R. Barker, “Electrical Imaging and its Application in Engineering Investigations,” Engineering Geology Special Publications, Geological Society, London, Vol. 12, No. 1, 1997, pp. 37- 43.
[10]	M. H. Loke, “Electrical Imaging Surveys for Environmental and Engineering Studies,” A Practical Guide to 2-D and 3-D Surveys, 1999.www.abem.se