Abstract
Beneath the mountainous countryside of North Korea snakes an extensive network of underground bunkers, protecting weapons and military resources from potential attack, experts believe. Kim Jong Il, North Korea's reclusive “Dear Leader,” has a reputation for paranoia, but he's far from the only one digging deep.
More than 1,400 underground military hideaways worldwide shelter military assets such as missiles, uranium enrichment facilities, biological and chemical weapons, and command and control centers, according to the Defense Department. Underground lairs–especially the difficult to kill “hard and deeply buried targets”–have gotten under the skin of U.S. Defense officials, who want to develop new types of earth-penetrating, “bunker-busting” nuclear weapons to use against these facilities. According to the Bush administration's 2001 Nuclear Posture Review, a “more effective earth pen-etrator” would allow both low- and high-yield nukes to “defeat” a larger array of underground targets, and in the case of low-yield weapons, do so with less radioactive fallout.
But most experts say that new nuclear weapon designs are unlikely to improve how deep earth penetrators can burrow, and they warn that these warheads would still produce significant amounts of fallout, a fact recently confirmed by Linton Brooks, the head of the National Nuclear Security Administration, in congressional testimony. Additionally, certain factors–like weather–will always be beyond the control of war planners, but will play a large part in determining the extent of damage a nuclear weapon does.
What would actually happen if the United States were to strike a buried target with an earth-penetrating nuclear weapon? Recent research gives an idea of the answer–and it might give pause to those who see bunker-busters as the answer to underground annoyances.
Even a very small weapon would cause a great deal of deadly damage, according to Thomas Cochran and Matthew McKinzie of the Natural Resources Defense Council (NRDC). To spell out just how much, they examined the likely effects of an attack against a prototypical buried facility: the underground hangars at Pukch'ang Air Base in North Korea. Using Hazard Prediction and Assessment Capability software from the U.S. Defense Threat Reduction Agency, the researchers compiled casualty predictions for a single-weapon attack of various yields against Pukch'ang. Not only would casualty rates be high, but they determined that radioactive fallout could be extensive, affecting far more than the northern half of the Korean Peninsula.
The fallout's reach
The detonation of a 400-kiloton nuclear weapon (equivalent in yield to the only earth-penetrating nuclear weapon in the U.S. arsenal, the B61-11 bomb) could produce a fallout pattern as shown. Assuming that the attack occurs in January, Cochran and McKinzie estimate that between 30,000 and 35,000 casualties would result from the explosion's blast, heat, and initial radiation. During the first 48 hours after the attack, more than 250,000 people could be exposed to significant levels of fallout.
Low yield, still deadly
Casualty rates from a nuclear strike against Pukch'ang would vary greatly according to the weapon yield, the time of year, and the weather at the time of attack. Cochran and McKinzie predict that in the weather conditions most favorable for low casualty rates, a single 5-kiloton warhead could still cause more than 5,000 deaths and injuries within 48 hours of the attack, due mainly to unshielded fallout exposure.
Burying the target: Pukch'ang's underground hangars
Pukch'ang Air Base is located 55 kilometers northeast of Pyongyang along the Taedong River. A March 2002 satellite photo (part of which is shown above) revealed 60 Soviet-made fighter aircraft stationed at Pukch'ang, including 31 MiG-23 Floggers. Decades ago, Floggers were a nuclear-capable asset in the Soviet Air Force. The photo also shows entrances to several underground hangars, nestled into a nearby hill.