Differences in scaled height of burst between the three shots are includedin the values of the coefficient K. A cursory study suggests that in fact K may be represer.ted as a constant modulated by a negative exponential of the 1.5 power of the scaled height of burst. However, the data are hardly strong enough to support an analytical expression of such complexity. Equation 1.1 yields reasonable estimates for vertical or radial ground-transmitted accelerations within the scaled ground-range limits 2.5 = Ap = 10 when the proper coefficient K is used. For near surface bursts, between zero burst height and a scaled height of 0.14 ft/lb, K may be estimated roughly between 2.66 x 10° and 2.1 x 105 without excessive increase in the acceleration error. In any event the error in derived accelerations will probably be less than +50 per cent and should be adequate for estimating set ranges and possibly for rough estimates of damage. "CT = Tity T Titty ‘ a 1.0 3 ° / —— 9 TTI y — ~ 0.4 = oo, 0.4 A= 0.053P"? L- 10 EL tyit _ 40 OVERPRESSURE, PSI tt th 100 Fig. 1.7—~Air-shock induced acceleration as a function of incident overpressure for Mike shot, Operation Ivy. Absolute values of maximum positive and negative vertical accelerations induced by inci- dence of air shock above the gauges are plotted as a function of peak air overpressure in Fig. 1.7. The end points of the vertical line segments representthe positive and negative peaks, negative being the greater at all stations. Overpressures are mean peak values except at Station 650.01, where an estimate was made by extrapolation since dependable overpressure data were not obtained at Bogon. Peak accelerations induced at Station 603 by air shock are higher by a factor of about 7 than would be expected from interpolation of the ground-motion data. The straight line fitted to the data in Fig. 1.7 represents the equation A = 0.053p!"? . in which acceleration is in g units and overpressure is in psi. 23 (1.2)