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elevation using compass, hand level, and measuring tape methods. <br />Locations and elevations should be considered approximate. <br />The data reduction and interpretation procedure consisted of <br />the following sequence of tasks: <br />o visually picking first breaks of compression waves (P-waves) <br />from the analog records of the oscillograph / seismograph system, <br />o plotting of time -distance graphs utilizing the raw data, <br />o preliminary determination of apparent velocities, <br />o plotting of elevation data along the profiles, <br />o measurement of differences between actual geophone <br />elevations and a constant -slope profile, <br />o computer analysis of preliminary apparent velocities and <br />elevation differences to determine travel -time corrections, <br />o adjustment of the time -distance graphs and refinement of <br />apparent velocity determinations satisfying reciprocity, <br />o comparison of time -distance and, velocity data with a catalog <br />of subsurface structures to interpret an appropriate seismic <br />refraction model, <br />o computer analysis (computer program by Shires, 1983, <br />principles published by Mooney, 1977, Handbook of Engineering <br />Geophysics, utilizing the condition of reciprocity, travel -time = <br />distance / velocity, and Snell°s Law of Refraction) of apparent <br />velocity and intercept time data to determine depths of <br />refractors, true velocities, dips of refractors. and angles of <br />seismic raypaths, <br />o measurement of time deviations from "best fit00 apparent <br />velocity slopes on the time -distance graphs, <br />o computer analysis of apparent velocities and time deviations <br />to determine refractor profile corrections, <br />o adjustment of refractor depths to reflect time deviations, <br />o correlation of results with known geologic factors tfrom <br />mapping and borehole logs) and adjacent or overlapping seismic <br />refraction data, and <br />o final preparation of interpreted subsurface velocity <br />profiles. <br />The equipment used for the seismic refraction survey <br />consisted of 12 geophones at one time of 4.5 Hz natural <br />frequency. The geophones were connected to 25 -foot take-out <br />spacing cables using Mueller clips. The seismograph used was a 24 <br />-channel Texas Instruments Explorer 3500 Model. The oscillograph <br />