Electrical Resistivity Survey

Electrical Resistivity Sounding has been in use since 1913 and went through major developments during the1980s. Since 1990 the electrical imaging technique has also undergone major development. The two techniques differ in their approach and are suited to investigating different geological situations. Both rely upon the variability in electrical resistivity exhibited by earth materials and utilise an array of four electrodes implanted into the ground surface. The commonest two arrays are th...
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MASW Survey

Multichannel Analysis of Surface Waves Method (MASW) is a seismic exploration method evaluating ground stiffness in 1-D, 2-D, and 3-D formats for various types of geotechnical engineering projects. Since its first introduction in the late 1990s, it has been utilized by many practitioners and researched by many investigators worldwide. MASW first measures seismic surface waves generated from various types of seismic sources—such as sledge hammer—analyses the propagation velocities of thos...
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Seismic Refraction Survey

The seismic refraction method is based on the measurement of the travel time of seismic waves refracted at the interfaces between subsurface layers of different velocity. Seismic energy is provided by a source located on the surface. Energy radiates out from the shot point, either travelling directly through the upper layer (direct arrivals), or travelling down to and then laterally along higher velocity layers as refracted arrivals before returning to the surface. This energy is detected on...
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Seismic Reflection Survey

Seismic reflection profiling involves the measurement of the two-way travel time of seismic waves transmitted from surface and reflected back to the surface at the interfaces between contrasting geological layers. Reflection of the transmitted energy will only occur when there is a contrast in the acoustic impedance (product of the seismic velocity and density) between these layers. The strength of the contrast in the acoustic impedance of the two layers determines the amplitude of the re...
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Seismic Survey

Seismic Techniques are commonly used to determine site geology, stratigraphy, and rock quality. These techniques provide detailed information about subsurface layering and rock geo-mechanical properties using seismic acoustical waves. Reflection and Refraction are the most commonly used seismic techniques. These methods determine geological structure and rock velocities by either refracting or reflecting waves off boundaries between rock units with different seismic velocities or impeda...
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