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~3ge 3 • Also oz the fime is a series of vertical lines. This is a time scale' the interval betweun adjacent line; is .02 or 1/50th of a second. This scale is Wised in claculating atmu~pheric overpressure, particle dis- placement, or particle acceleration. The seismographic film -records obtained o±i 6-19 and 5-20-79 will he kep*_ in our files for further reference should a deed arrise. RESiJLTS: For the blast of i-19-79 at the locatio~.~ of the Wells property, the LED display on the seismograph in- dicated no vibration particle velocity recordings in any of the three components, nor was there any recording oE~ air blast. The blast was not perseptable to either the writer or 14r. Robert 1de11s wllo cans standing near by. No indication of the sho*_ was recorded on the film record, which is more sensitive tha;i the LED display. For the blast of 5-20-79, with the seismograph set up adjacent to the Yourlis Ranch Road, the following • results were obta;,zed. MAY.Ii~IUM PARTTCLE COMPONENT MONITOR VELOCITY inches er second) Transverse 0.0 0.03 inches per second 'lerticle 0.0 0.09 inches per second Lo~igitudinal 0.1 0.14 inches per second Peelc Sound Pressure 0.2 0.00'? psi = 117 decibles DISCUSSIOAT OF RES:]LTS Seismological research by go~aernment agencies, insurance co~.npanies, and qualified individuals has es- tablis'.zed standards relating ground vibra~io~i levels to structural damage. A safe level, as estab1is11ed icy the [3. 5. Bureau of Mines, is defined as one in which a particle velocity of 2.0 inches per second .is not exceeded on any one of the three compo:ents of motio:t. This figure is widely accepted a; a reasonable limit for the around motio_i from blasting. Recent OSM re,~,ulations have reduced this acceptable level to 1.0 inches per second. Both of the above limits are conservative as shown by the criteria noted in the following tab Le. •