RE: This design could disrupt P-wave
We see similar things in everyday designs - noise cancellation, innate sound deadening. If you can create what are known as destructive interference and resonance conditions, then P-wave amplitudes might be greatly reduced. The horizontal tunnel combined with engineered zigs and zags might have been a crude attempt at concealment.
>>been a crude attempt at concealment.
Or obfuscation of failure.
What does Mr. seismograph say about the similarity of this event and previous Nork warblings?