US runs underground test to detect 'decoupled' nuclear blasts

The NNSA conducted an underground chemical explosive test in Nevada to improve detection of hard-to-detect 'decoupled' nuclear detonations. The non-nuclear test, tied to a suspected Chinese test at Lop Nur in 2020, used seismic, infrasound and electromagnetic sensors.

• Blast took place in a tunnel at the Nevada site 65 miles from Las Vegas
• Accelerometers, seismometers, infrasound and electromagnetic sensors used
• 'Decoupling' in a large chamber muffles seismic signals of an explosion
• US has kept a moratorium on nuclear explosive tests since 1992