Abstract

For equivalent TNT energy yields of 180 pounds to 19.2 kilotons at distances of 0.3 to 3200 kilofeet, a yield scaling law of W0.75 is indicated. Maximum earth particle displacements satisfy an exponential attenuation function of the form:

 
A=CW0.75Dn×10kf0.8D

where A is maximum earth particle displacements in centimeters, C is a constant, W is yield in tons, D is distance from detector to source in feet, n is a wave propagation constant, k is a constant and f is the visually dominant frequency in cps of the measured pulse on the seismogram.

For distance of 0.3 to 9.8 kilofeet, C is 104.57, n is 2, and k is 1.75 × 10-6; from 9.8 to 525 kilofeet, C is 100.6, n is 1, and k is 1.83 × 10-6; from 525 to 3200 kilofeet C is 10-2.82, n is 0.5, and k is 7.6 × 10-7. The frequency exponent in the 525 to 3200 kilofeet range is negligible since the maximum displacements were observed to occur near one cps. Stations on desert alluvium recorded displacements 2 to 4 times greater than indicated by the above scaling functions.

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