Role of geology in assessing vulnerability of underground fortifications to conventional weapons attack

The military use of subsurface geologic environments dates back at least 5,000 years to Mesopotamia and Egypt, and continues to be a critical element in planning for both tactical and strategic military activities worldwide. In the context of present-day concerns of "proliferation," the concept of geologic barriers and how best to defeat them has taken on new meaning. Characterization of the geology and the engineering properties of materials surrounding and constituting a deeply buried bedrock underground military facility (UGF) is of great military interest The degree of success of employing conventional munitions against such UGFs will be limited by our ability to understand the matter/energy interactions between penetrating conventional warheads and rock environments. Geotechnical information that can be used strategically to evaluate the vulnerability of UGFs is herein defined as "strategic geologic intelligence" and includes lithologic characterization; intact mechanical, weight/volume, penetrability; and interpreted in situ engineering properties of geologic units proximal to UGFs. Geologic vulnerability of UGFs can be considered primarily a function of three variables: depth, rock-mass strength, and surface-layer penetrability. To the degree that any bedrock UGF is vulnerable to conventional weapons attack, the availability of appropriate site characterization data significantly increases one"s ability to choose optimal weapons and tactics to defeat UGFs. Thus the role of "strategic geologic intelligence" in future war planning cannot be overstated.