Empirical analysis of seismic records for eleven nuclear tests at the Nevada Test Site

Regional seismic records for eleven underground nuclear explosions were processed and analyzed (empirically) in a search for source and path related patterns in the signals. These nuclear tests were conducted between August, 1979 and April, 1980; all were located in Yucca Flat at the Nevada Test Site (NTS). The seismic signals generated by these explosions were recorded on the LLNL four-station network, located at distances of 200 to 400 km from the NTS. Amplitudes were measured for consistently recorded vertical component body waves, and for vertical and transverse components of surface waves. Correlation between phase amplitudes was statistically determined, and amplitude ratios were compared for four stations for the same event, and at a single station for the complete set of events. Previous studies have shown that certain amplitude ratios are relatively unaffected by the size of the explosion but sensitive to propagation effects. For this set of events, we do not find a statistically significant change in the ratio of Pg:Lg due to different propagation paths to the four stations. We do, however, find increased variability in the amplitude measurements for the smaller events in the population considered in this study

Strengthening International Nuclear Forensic Capabilities Through Collaborative Science In Ukraine STRENGTHENING INTERNATIONAL NUCLEAR FORENSIC CAPABILITIES THROUGH COLLABORATIVE SCIENCE IN UKRAINE

ABSTRACT Globally, the production, transport and storage of nuclear materials have led to serious concerns over illegal trafficking of such materials. Ukraine stands at one of the geographical crossroads of such activities, and contains the largest uranium ore reserves in Europe. Moreover, Ukraine retains significant waste from Soviet-era uranium production and enrichment activities, as well as radioactive materials accumulated from the Chernobyl catastrophe. Lawrence Livermore National Laboratories (LLNL), with support through NA-242, has initiated multiple cooperative efforts within Ukraine, engaging some of the best Ukrainian scientists and institutions in nuclear forensic science. Nuclear forensics serves as a vehicle for scientific collaborations between the Ukrainian and United States governments, strengthening the response and core capabilities of Ukraine, who is also taking an active role as the regional leader in nuclear forensics, and additionally contributing to further engagements between respective governments. These collaborations are being supported through the Department of Energy, NA-242 GIPP (Global Initiatives for Proliferation Prevention) and CBM (Confidence Building Measures) programs, and serve to enhance nuclear forensics capabilities for Ukraine and neighboring countries, as well as in the United States. INTRODUCTION Ukraine stands at a geographical and geopolitical crossroads for illicit trafficking of nuclear materials, possessing the largest uranium ore reserves in Europe, as well as retaining significant waste from Soviet-era uranium production and enrichment activities, and radioactive materials accumulated from the Chernobyl catastrophe. Additionally, Ukraine supports a large uranium mining industry founded on a diverse set of geological settings and employing multiple uranium mining technologies, from open-pit to leach field mining. According to the illicit trafficking database maintained by the International Atomic Energy Agency (IAEA) [1,2], over the past two decades, more than one thousand cases have been confirmed by States Points of Contact, about 25% of which involved nuclear materials. Interdictions on nuclear materials, including samples consistent with origins in the former Soviet Unio