>>8642330 (lb)

>>8642365 (lb)

Hard to tell which trace it looks more like.

https://whyfiles.org/305detect_nuke/

Surfing that wave

Mine collapses are one seismic event that could be mistaken for an explosion, because both make a lot of pressure waves, but the seismograph line starts to fall with a mine collapse, while it rises after an explosion.

Eliminating mine collapses and earthquakes leaves you with an explosion, but is it chemical or nuclear? Here, size matters. A small nuclear explosion, like North Korea's 2006 test (estimated at 0.6 kilotons of TNT), could conceivably be faked with chemical explosives. But even if you manage to detonate 600,000 kilograms of high explosive all at once, digging the requisite hole would probably be visible to a spy satellite.

We asked Clifford Thurber, a professor of geophysics at University of Wisconsin-Madison, about seismic detection of nuclear blasts. Thurber, who has explored how seismic signals can be used to locate nuclear tests, says estimates of an explosion's size can be "shockingly variable," because the intensity of seismic signals greatly depends on the Earth's internal structure, which is "not a spherical ball of uniform material."