New comunication tech via seismic waves ?

Already used by some animals and insects at much smaller scale.

https://en.wikipedia.org/wiki/Seismic_communication

Rayleigh waves :

https://en.wikipedia.org/wiki/Rayleigh_wave

First recorded trial of this kind of signal was on May, 12th, the signal crossed the whole US and have been recorded successively on all seismic recorders.