Earth Drums

Can seismic waves be used for cross-Earth data transfer and communications?

First, there are serious problems with existing forms of communication. Satellites and fiber-optic cables are both vulnerable to sabotage, as well as to accidental destruction. The various powers of the world have demonstrated the ability to use ballistic missiles to destroy communications satellites even in high-Earth orbit, and have designed and built submersible vehicles with the specific purpose of severing deep-sea cables.

By comparison, seismic data transmission would be a much slower method of communication, but also virtually fail-safe. Seismic waves travel at around 10km per second, which means traversing the entirety of Earth's 12,742km diameter would take approximately 21 minutes or so. But a single source of such data would theoretically be able to communicate with any detector on the Earth.

Another potential flaw would be the lack of confidentiality of the communications. The data itself could be encrypted, but there would be no guarantee that it was not being spied upon by eavesdroppers.

So clearly seismic data transfer would in many ways not be ideal. But it would nevertheless be a decent backup system in the event that more traditional means of communication were unavailable.