"Notice how there is no build up on the California EQ on the right. And on the left a normal EQ how there is some build up with sustained shaking. Cali EQ decays immediately with no small aftershocks after. This is highly indicative of explosions or man made disturbance.

Not to mention eyewitness accounts saying it was a strong jolt with a decay rolling quake after."

https:// boards.4chan.org/pol/thread/166911427#p166911428