CHAPTER 3Materials and Methods3.0 Background3.1 Seismic TheorySeismic Energy SourceEnergy is one of the main sources for conducting the seismic method. The seismic source produces a signal in the ground to determine the penetration depth and a high-resolution image underground. According to Stark (2008), energy that upsets equilibrium conditions produces mechanical waves known as seismic energy. Seismic source divided into 3 types: impact, impulsive and vibratory as categories on land, in water and in well (Reynolds, 2011). Table 3.1: Type of seismic source and location of use (Modified from Reynolds, 2011) Seismic source On land On waterSledgehammer impact, weight drop, accelerated weight. Pulse dynamite, detonating fuse, air rifle, shotgun, well spark. Air gun, gas gun, sleeve gun, water gun, steam gun, pinger, boomer, sparker. Vibroseis vibrator, vibrating plate, Rayleigh Multipulse wave generator, Geochirp. It is important to choose suitable sources to create energy since there is always a trade-off between depth and minimum resolution. To achieve high penetration depth, a low frequency source was applied, but the subsurface resolution is poor. Whereas, to obtain high subsurface resolution, the source must be high frequency, but unfortunately the penetration depth is low (Reynolds, 2011). Seismic Wave Detection Seismic survey would not be able to be performed without the use of a detector for signals returned by the sensor. The sensors are called geophones used on land and the combined weight of a geophone is the hydrophone used in marine seismic and water-filled wells (Reynolds, 2011). Geophones consist of a cylindrical magnet with ... half of paper ... g conducted to check for any possibility of discontinuities in the seismic traces (Reynolds, 2011). Borehole TheoryAccording to Prensky (1999), it is important to correlate the borehole, sedimentology, stratigraphy and structural analysis. In this modern situation, the borehole is also applicable in core orientation, characterization of fractures, grain size, porosity, faults, bedding and many others. The Standard Penetration Test (SPT) uses a heavy hammer weighing 63.5kg falling from a predetermined height of 760mm from the top of the drill pipe. Counted the number of shots for a penetration of 450 mm. The number of shots measured up to the depth of 150 mm was ignored as it may have some disturbing effect on the drilling. The next depth of 300mm is the actual shot count, N. SPT is important for testing clays and granular soils at the lowest cost (Potts and Zdravkovic, 2001).