Americans were happily ignorant of US nuclear testing for decades. Under baby shrub, the Nuclear Test Ban Treaty was thrown out the window.

That said, I haven't heard that particular rumor. Perhaps it is confused and mixed up with the blasting of fault lines by the USGS, to learn more about how earthquakes happen?

That particular aspect of the research (using satellite imagery to record seismic and sound waves) is known as crustal structure research. Only research conducted on land uses explosives to artificially generate seismic waves. Underwater research at sea uses an air gun type thing that releases highly pressurized air from a container.