[cowboysauce]

Almost certainly not. A nuclear detonation would also produce noticeable seismic effects as well as release iodine-131, which was not detected.

[etimberg]

https://thebarentsobserver.com/en/ecology/2020/06/various-re... reports that Iodine 131 was measured in Norway during the week of June 2-8.

[guerrilla]

Ok, but that's two weeks off from this detection.