May 28, 2026
4 MIN READ
Underground acoustic signals reveal hidden tunnels
Researchers at ORNL developed a new method to detect underground tunnels by sending acoustic signals upward from below the ground rather than downward from the surface. In testing, the method revealed tunnels through unique low-frequency signals created when sound waves bent around the underground structure. This technique could improve detection of hidden voids that threaten roads, railways, and other critical infrastructure.
