Telecommunication through geological layers using seismic waves

This work investigates the feasibility of transmitting information through geological layers using seismic waves. It is a part of developing wireless underground communication alternatives for the Internet of Underground Things (IoUT). Experiments were conducted at the ANDRA Underground Research Laboratory to transmit for the first time data from 490 m depth to the surface. To that end, we used about 20–25 wavelengths at frequencies [103 Hz -124 Hz] with Vp = 2500 m/s. These small size data (17×11-pixel image) were encoded using the Hamming (7, 4) code. Each pixel was converted to frequency activations and transmitted from an underground tunnel to 30 geophones deployed on the surface. Time–frequency analysis enabled identification of emitted frequencies. Using threshold-based frequency detection followed by Hamming error corrector, the transmitted image was successfully reconstructed. Stacking five repeated experiments significantly improved the signal-to-noise ratio and reducing pixel errors. Although only a few errors were observed in this small test case, larger and more complex datasets are expected to better challenge the robustness of the Hamming code. These findings show the potential seismic waves as a viable communication method in deep geological environments. It also emphasizes the necessity for adaptive decoding algorithms and further testing with larger images.