the variability in results that can be obtained for different scenarios when considering plausible ranges in parameters.

At least three key sensitivities affect estimates of military effectiveness and casualties associated with use of a nuclear EPW or a nuclear surface-burst weapon:

  1. Target location, especially urban versus rural;

  2. Accuracy of weapons delivery (circular error probable) and precise knowledge of target location and structure, as military effectiveness depends strongly on a combination of accurate delivery and yield; and

  3. Estimates of the source, transport, and influence on populations of the effects of a nuclear explosion, as these can be highly variable (by factors of up to about 10 to 1,000, depending on assumptions).

One additional sensitivity affects estimates of the effects of the nuclear EPW:

  1. Functionality after penetration, especially as influenced by target heterogeneity and its uncertainty (e.g., local geology or complex structures in urban areas).



Scaled depth of burst (DOB) is a normalization of the actual depth (or height) of a burst based on weapon yield to that for a 1 kiloton weapon. This is determined by DOB/Y1/3. Thus, the scaled DOB and actual DOB are the same for a 1 kiloton EPW. For example, a 1 kiloton weapon buried 3 meters has a 3 meter scaled DOB, whereas a 300 kiloton weapon buried at the same depth of 3 meters couples its energy to the ground as if it were a 1 kiloton weapon buried at an actual depth of about 0.45 meter; that is, 3/3001/3 = 3/6.67 = 0.45.


Defense Nuclear Agency. 1991. Effects Manual Number 1 (EM-1), Chapter 3, “Cratering, Ejecta and Ground Shock,” DNA-EM-1-CH-3, Alexandria, Va., December.

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