If an underground explosion occurs anywhere in the world, there is a good chance that a seismologist can pinpoint it. However, they won’t necessarily be able to tell you what kind of explosion had occurred—whether it is chemical or nuclear in nature. New research from Pacific Northwest National Laboratory (PNNL) scientists makes detecting nuclear explosions easier.
“To a seismologist, chemical and nuclear explosions look identical,” said Harry Miley, Laboratory Fellow and physicist in the National Security Directorate at PNNL. “Radionuclide detection technologies, like the PNNL-developed Xenon International and Radionuclide Aerosol Sampler/Analyzer, known as RASA, can discriminate between the two by detecting radioactive atoms that are created in nuclear explosions. However, we have very little scientific understanding of the geologic containment of these atoms following an explosion.”
When an underground explosion occurs, gases travel through fractures in the ground and escape into the atmosphere. Instruments such as Xenon International and RASA can then detect radionuclide gases, but their chemical signatures may be greatly affected by rock damage that the gases must pass through.



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