No, I don’t believe they are extra-terrestrial.
Gravity surveys (basically a spring in a box) carried out in Britain are sensitive enough to detect, and require correction for, big Atlantic waves breaking on the Irish coast. The seismic wave generated in the subsurface rock is distinctive because it has a period of 12 seconds. There's really so much that exists just beyond our senses...There's a lot of stuff like this. There's some interesting deep sea sounds maybe related to continental plates, i.e. you can possibly "hear" the low resonance vibrations of the plates moving, but mention of them often devolves into "the Cloverfield monster isn't real lol". I work and teach a few areas affected by stuff like this and it can get tiring.