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GEOHORIZOAIS January 2005 '29 <br />Energy Source Comparison (Digipulse versus <br />Vibroseis) <br />Comparison tests between the Digipulse AWD and <br />Vibroseis similar to the dynamite source comparison have <br />not yet been conducted. However, basic seismic signal theory <br />indicates that the most ideal energy source signature for <br />seismic exploration applications is a spike wavelet. Dynamite <br />sources are the closest to this wavelet character and are <br />therefore frequency rich for the bandwidth of interest. <br />Although the Digipulse source signature (impulsive) shows <br />a greater rate of signal attenuation with increasing frequency, <br />its amplitude and phase characteristics are remarkably close <br />to the dynamite signature, with nearly all of the energy <br />generated over a very short time. Vibroseis sweep signals are <br />quite different and should be compared to the Digipulse in a <br />different manner. Since the Vibroseis system is also a surface <br />source, it too suffers the same near surface signal attenuation <br />as the Digipulse. To increase overall total energy, multiple <br />Vibroseis sources are used simultaneously, and various sweep <br />configurations can be used to optimize the cross - correlation <br />process. While we cannot necessarily dispute the performance <br />of Vibroseis in general, a clear disadvantage for using <br />Vibroseis concerns cost, logistics, and environmental <br />problems. <br />Accelerated Weight Drop 450 Ib - YouTube <br />www. youtube. com/watch ?v= JV3KsH5YZUw <br />Added Mar 18, 2009, Accelerated weight drop <br />mounted on a IC -35 track unit.... <br />