TITLE:
Integration of Seismic Refraction and 2D Electrical Resistivity in Locating Geological Contact
AUTHORS:
Nisa’ Ali, Rosli Saad, M. M. Nordiana
KEYWORDS:
Geological Contact; 2D Electrical Resistivity; Seismic Refraction
JOURNAL NAME:
Open Journal of Geology,
Vol.3 No.2B,
October
22,
2013
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.