I have no idea. I don't know if even was a signal or just a focus of energy. All I know it is propagated like a signal and had what appears to be a dual wave nature.
But my research sent me to the telegraph and Edison, and multiplexing of information.
I did find it odd that it seemed to last be recorded in Hawaii. The place of NSA stuff from long ago and possible missile launch averted.
Just not a naturally occurring waveform is all I am saying that is why it is interesting enough to dig on.
11/11/2018 Just before 9:30 not sure of time zone.
https://www.independent.co.uk/news/world/earthquake-seismic-waves-mayotte-madagascar-volcanic-activity-science-a8659236.html?amp&__twitter_impression=true
it was off the east coast of Africa between Africa and Madagascar.
So basically it was not a naturally occurring wave!!!! Too symmetrical, too focused, and propagated in an unusual way.
Geologists are going with lava flow under the ocean and collapse of a lava dome causing a resonate reaction in another chamber. I don't buy it - too symmetrical and propagation that far? Does not hold up.
Submarines have been using ELF communications for a long time.
That wave was both longitudinal and Transverse
With symmetry not seen in normal quakes.
Sauce on quakes:
http://www.geo.mtu.edu/UPSeis/waves.html
What is the likelihood that a 2 something quake could propagate half way across the world?
A 2 something shake - we would not feel.