The National Nuclear Security Administration (NNSA) recently led an experiment designed to improve the United States’ ability to detect underground nuclear explosions using conventional and advanced detection technology. This experiment was the fourth in a series of experiments conducted since 2011.
The experiment tested many detection tools, such as: high-resolution accelerometers, infrasound, seismic, explosive performance, electromagnetic, ground-based LIDAR (light detection and ranging), digital photogrammetry data, and satellite-based interferometric synthetic aperture radar (InSAR).
InSAR is a new detection technique, which can measure the earth’s subsidence after a disruption, thus pinpointing the location of a nuclear test rather than measuring its yield. As David Hafemeister stated in Arms Control Today, “[InSAR]’s accuracy of 0.01 square kilometers is vastly better than the [Comprehensive Test Ban Treaty] CTBT’s allowed upper limit of 1,000 square kilometers.” More information on InSAR can be found in this article.
Hailing the experiment as “successfully conducted”, the NNSA stated in a May 26 press release that the “Source Physics Experiment (SPE-4 Prime) is a fundamental step forward in the U.S. effort to improve arms control verification, and will eventually be used to assure compliance with the Comprehensive Nuclear Test Ban Treaty (CTBT).”
According to the Las Vegas Review-Journal, the experiment used a chemical explosive that was detonated in Area 15, in the northeast corner of the Nevada National Security Site (NNSS). The detonation was equivalent to 196 pounds of TNT and was discharged in a granite formation 286 feet below the surface.
According to Anne Harrington, NNSA deputy administrator for defense nuclear nonproliferation, “The seismic Source Physics Experiments substantially advance the United States’ efforts to develop, validate and improve on emerging technology. The work conducted at the NNSS and by the NNSA’s Defense Nuclear Nonproliferation programs serves to advance the implementation of President Obama’s nuclear nonproliferation agenda.”