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Evaluation of Vibration at the Benson Brothers Red Shale Quarry <br />• would not have received any vibration readings. Therefore I chose this location knowing <br />the unit would collect some data. <br />This letter report includes a brief technical review of ground vibrations typically caused <br />by mechanical equipment and a summary of the vibrations measured at the Red Shale <br />qu~'Y .• <br />Ground Vibration Induced by Construction Equipment <br />When excavation and heavy construction equipment is operated as was done at the Red <br />shale Quarry vibration is induced in the ground and adjacent structures. In ground just <br />beyond the zone where physical disturbance is caused by excavation work or heavy <br />equipment, stress waves spread through the ground mass and along the ground surface. <br />Some waves pass through the "body" of the ground. Primary compression waves and <br />shear waves are examples of body waves. Other surface vibration waves travel along the <br />ground surface similar to the way waves travel along the surface of water. The energy in <br />theses waves is transmitted through the ground as a series of elastic stress pulses <br />transferred from particle to particle within the ground or rock mass. When seismic waves <br />pass through the ground, ground particles oscillate within three-dimensional space. <br />• <br />Abbreviations: <br />SH =Shear wave, horizontal <br />SV =Shear wave, vertical <br />R =Rayleigh wave <br />P =Compressional wave <br />V~a~6 a+'`e~~ P <br />SH <br />~ ~ <br />SV <br />Detonating R <br />Charge or other <br />Impulsive <br />Disturbance <br />Figure 1 -Typical Vibration Waves <br />• <br />PreSeisTek, Inc. Page 2 of 4 8/28/2008 <br />