Communications Via Seismic Waves Employing 80-Hz Resonant Seismic Transducers

The design, construction, deployment, and operating characteristics of experimental 80-Hz resonant seismic transmitterand receiver-transducers are discussed. A description is given of seismic-acoustic measurements and experiments involving 80-Hz signal transmissions 1) between surface sites in flat terrains, 2) between surface sites in mountainous terrains, 3) between locations on lake ice, and 4) from a surface site to locations underground inside a deep mine via earth, ice, and water media. Results of these experiments are evaluated with regard to the realization of "hard line" communications capabilities by seismic-acoustic and electrical means.