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Introduction Ground penetrating radar (GPR), Seismic and resistivity
surveys are useful geophysical
methods for use in near surface mapping studies. GPR uses a high frequency (MHz)
electromagnetic pulse that is transmitted from a radar antenna to the ground
surface. The transmitted pulses are then reflected by the ground into a radar
receiver. The results obtained from the reflected material depend on the
dielectric properties of the subsurface and the type of material encountered.
The GPR data can be used to study the condition of subsurface, contaminants
in groundwater, subsurface faulting, and underground cavities. By knowing the
condition of the subsurface potential geological hazards can be detected (Werkema, 2000). The 2D electrical resistivity survey is
carried by making certain measurements to determine the subsurface
resistivity distribution on the ground surface. In this method, the centre point of the
electrode array remains fixed, but the spacing between the electrodes is
increased to obtain more information about the deeper sections of the
subsurface(Dahlin,
T. 1993.)
.The resistivity of the ground surface depends on the properties of soils and
rocks. Some of the properties affecting resistivity are mineral content,
water content, porosity and degree of saturation in the soil or the rock. The
resistivity method is being used for hydrogeological,
mining and geotechnical investigations (Dahlin, T. 1993.). The seismic survey is used for measuring
the earth’s geophysical properties by means of physical principles such as
magnetic, electric, gravitational, thermal, and elastic theories. It is
based on the theory of elasticity and therefore tries to deduce elastic properties
of materials by measuring their response to elastic disturbances called
seismic (or elastic) waves. These three methods were used by the |