Luke J. Kluchko Vladimir Konovalov Gerard Vouille William S. Leith 2002 <p><span>Degelen mountain, located in </span><span class="searchword">Eastern</span><span class="searchword">Kazakhstan</span><span> near the city of Semipalatinsk, was once the Soviets most active underground </span><span class="searchword">nuclear</span> <span class="searchword">test</span> <span class="searchword">site</span><span>. Two hundred fifteen </span><span class="searchword">nuclear</span><span> tests were conducted in 181 tunnels driven horizontally into its many ridges--almost twice the number of tests as at any other </span><span class="searchword">Soviet</span><span> underground </span><span class="searchword">nuclear</span> <span class="searchword">test</span> <span class="searchword">site</span><span>. It was also the </span><span class="searchword">site</span><span> of the first </span><span class="searchword">Soviet</span><span> underground </span><span class="searchword">nuclear</span> <span class="searchword">test</span><span>--a 1-kiloton device detonated on October 11, 1961. Until recently, the details of testing at Degelen were kept secret and have been the subject of considerable speculation. However, in 1991, the Semipalatinsk </span><span class="searchword">test</span> <span class="searchword">site</span><span> became part of the newly independent Republic of </span><span class="searchword">Kazakhstan</span><span>; and in 1995, the Kazakhstani government concluded an agreement with the U.S. Department of Defense to eliminate the </span><span class="searchword">nuclear</span><span> testing infrastructure in </span><span class="searchword">Kazakhstan</span><span>. This agreement, which calls for the "demilitarization of the infrastructure directly associated with the </span><span class="searchword">nuclear</span><span> weapons </span><span class="searchword">test</span><span> tunnels," has been implemented as the "Degelen Mountain Tunnel Closure Program." The U.S. Defense Threat Reduction Agency, in partnership with the Department of Energy, has permitted the use of the tunnel closure project at the former nuclear test site as a foundation on which to support cost-effective, research-and-development-funded experiments. These experiments are principally designed to improve U.S. capabilities to monitor and verify the Comprehensive Test Ban Treaty (CTBT), but have provided a new source of information on the effects of nuclear and chemical explosions on hard, fractured rock environments. These new data extends and confirms the results of recent Russian publications on the rock environment at the site and the mechanical effects of large-scale chemical and nuclear testing. In 1998, a large-scale tunnel closure experiment, Omega-1, was conducted in Tunnel 214 at Degelen mountain. In this experiment, a 100-ton chemical explosive blast was used to test technologies for monitoring the Comprehensive Nuclear Test Ban Treaty, and to calibrate a portion of the CTBT's International Monitoring System. This experiment has also provided important benchmark data on the mechanical behavior of hard, dense, fractured rock, and has demonstrated the feasibility of fielding large-scale calibration explosions, which are specified as a "confidence-building measure" in the CTBT Protocol. Two other large-scale explosion experiments, Omega-2 and Omega-3, are planned for the summer of 1999 and 2000. Like the Tunnel 214 test, the 1999 experiment will include close-in monitoring of near-source effects, as well as contributing to the calibration of key seismic stations for the Comprehensive Test Ban Treaty. The Omega-3 test will examine the effect of multiple blasts on the fractured rock environment.</span></p> application/pdf en American Geosciences Institute Ongoing research experiments at the former Soviet nuclear test site in eastern Kazakhstan text