Magneto-inductive seismic fence

A method for detecting seismic vibrations in a ground environment or a water environment, comprising the steps of:

• fully burying at least one sensor module in one of a ground environment and a water environment;
• sensing seismic vibrations in said one of a ground environment and a water environment using said at least one sensor module;
• generating signals representative of said seismic vibrations using said at least one sensor module;
• transmitting said representative signals from said at least one sensor module through said one of a ground environment and a water environment via magneto-inductive signals in the ELF to VLF range not to exceed 4000 Hz.

An intrusion detector system comprising:

• first means fully buried in one of a ground environment and a water environment for sensing vibrations caused by intruders and for generating intrusion signals representative of said vibrations;
• second means fully buried in said one of a ground environment and a water environment and coupled to said first means for transmitting said intrusion signals through said one of a ground environment and a water environment via magneto-inductive signals in the ELF to VLF range not to exceed approximately 4000 Hz;
• third means fully buried in said one of a around environment and a water environment for receiving said magnet-inductive signals and for demodulating said intrusion signals therefrom to form demodulated signals;
• and
• fourth means coupled to said demodulating means for broadcasting through the air RF signals representative of said demodulated signals.