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• <br />RECORDING LOCATION: <br />pale 7_ <br />The vibrations and at:no:~nheric overpressure prod,_iced <br />fro,n file tcao blasr_s Caere recorded on a Safeguard Seismic <br />rJll l.t II portable particle velo~~ity-rec o-rding se i:~mograph. <br />SSU II ~~418 was set up as follows; <br />6-i9-79 <br />Northwest cor~.ier of a concrete slab veranda in front <br />of the residence of Mr. Robert Wells, 55452 Highway 13 <br />and 789, appro~:imar_ely 13Z miles north of Meeker Golorsdo. <br />This location placed the seismograp~i approximately 7 <br />miles due .south from the blast. <br />6-20-79 <br />350 Feet East o.f Highcaay 13 and ?89 ou a flat rock <br />outcrop ledge appror.»na~_ely 10 feet above the road leading <br />to the '_:ourlis Ranch. This placed the seismograph app= <br />ro;:imate7_y 3,000 feet east sout~ east from the shot o: <br />6-20-79. <br />• THE SEISl~IOGR~P <br />The SaEag+~ard Sr'ismic iJr,i_ TI is ._ seismoorp :^,:aa- <br />ufactured to the specifications of Philip R. ?3erge~••s <br />Associates, Inc. It is a compact eortable instrume:it <br />which produces a film recording of particle velocity. <br />It also provides an ace~~rate LED display of particle <br />velocity in all three components of motion. <br />The film from the SSU II employed in this survey <br />contains four (4) lines or traces. One trace represents <br />the horizontal component o£ ground motion along the line <br />bet;aecn the blast and the seismograhil, and is called <br />"longitudinal" A second trace, "transver_se", represents <br />the horizontal componenet o` motion at right anglea to <br />the ahov~, and a third trace records vertical movement. <br />Ali ground motion is resolved into these three compoaent-s, <br />with the trace movement being proportional to the rate <br />of ground motion (particle velocity) at the recordi;ig <br />location. The SSU II magnification is 0.4 inch of trace <br />movement for 1.0 i~.~ch per second of particle velocity. <br />" Air Blast" is measured o~i a fourth trace. This <br />trace movement is proportional to the atmospheric over- <br />pressure (the deviation from normal atmospheric pressare) <br />• produced by a blast. This o,Jerpressure is measured in <br />pounds per square inc1.1 (psi); it can be converted to <br />decibles, the unit employed in noise ;measurement. <br />