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i <br /> Traffic Control Work Plan: High Resolution P-Wave Seismic (HRPW) Reflection to <br /> Map Subsurface Stratigraphy, NorthEast of Lodi, CA <br /> Following is the work plan for the captioned project: a P-wave 3D vibroseis seismic <br /> reflection survey located near Lodi, CA. Bay's traffic work plan will briefly cover our <br /> scope of work, data acquisition methodologies, traffic control, vibration monitoring and <br /> schedule. <br /> PURPOSE AND SCOPE OF WORK <br /> The area of interest will be investigated along seismic survey transects provided in <br /> Attachment 1 (Line Location Topographic Map and Line Location Description).Total <br /> length of seismic surveys (vibrators) on county roads is estimated to be approximately <br /> 7.5 miles. The connecting wire to the geophones will have multiple road "cable <br /> crossings. <br /> DATA ACQUISITION METHODOLOGY <br /> Bay Geophysical plans to use high-resolution compressional (P-) wave (HRPW) <br /> reflection seismic profiling. This method is non-intrusive and develops less than 1.0 <br /> vps/sec within 10 ft of base plate pad. <br /> Bay Geophysical will use its high-frequency P-wave vibrator (new generation IV[ <br /> EnviroVib Vibrators) as a source for this seismic survey. The EnviroVib is an articulating <br /> buggy weighting approximately 15,000 pounds. This vibrator employs a "focal point" <br /> circular vibroseis pad reducing decoupling and ground roll. The Vibroseis method of <br /> seismic data acquisition was developed in the early 1960s for oil and gas exploration. <br /> Fundamentally this method inputs a signal into the ground over a period of time. This <br /> signal is frequency modulated and is known as a "sweep." After recording, the signal is <br /> demodulated to recover the original signal. The Vibroseis method offers a number of <br /> distinct advantages over conventional (compulsive) sources: <br /> Noise rejection: Vibrators input a modulated (frequency modulated) signal into the <br /> earth. The signal received is demodulated via cross correlation. Generally this <br /> modulation process results in the rejection of ambient noise by up to 30 dB. Vibroseis <br /> surveys can be performed in extremely high noise environments such as high vehicular <br /> traffic. <br /> Frequency content: Higher frequencies can generally be obtained using vibrators <br /> because the input signal can be limited to those frequencies desired. Further, seismic <br /> sources usually emit signals that interfere with reflections from the subsurface (coherent <br /> noise). This type of noise can be avoided by shaping the frequency spectrum of the <br /> modulated Vibroseis signal. <br /> Power output of vibrators is adjustable. This allows for the reduction of certain types <br /> of coherent noise (i.e., noise generated by the seismic source) and is adaptable to <br /> structural and cultural facilities located along the survey transect. The source interval is <br /> nrinntahla nnri ctrn inti iral fnrilitiac ci inh ac hririnac ri dvartc ninalinac atn nra Avniriarl <br />