Pennsylvania State University researchers use thunder for subsurface mapping

Researchers led by Nolan Roth at Pennsylvania State University have discovered that the energy from thunderstorms can be used to explore the subsurface through seismic tomography. By treating thunder as a source of seismic waves rather than mere noise, the team can map what lies beneath the Earth's surface.

The study utilized four kilometers of existing telecommunications fiber optic cable under the university campus, employing a technique known as distributed acoustic sensing. This method transformed the cable into a sensor array capable of recording imperceptible vibrations. After analyzing the data, the researchers identified 458 reliable thunder-induced seismic events.

Using these vibrations, specifically Rayleigh surface waves, the team successfully created a map of the subsurface up to 100 meters deep. The results revealed four low-velocity regions, which may indicate the presence of fluids, fractures, or sediments. This approach functions similarly to a medical ultrasound, interpreting how waves interact with different materials to deduce their composition without the need for excavation.