Thunderquakes—seismic waves generated by atmospheric thunderstorms—offer a novel, renewable source for seismic imaging, demonstrated by Penn State researchers using a fiber-optic network as a dense array of sensors.

By leveraging existing underground fiber cables, the approach provides a potentially cost-effective, continuous method for shallow subsurface monitoring and mapping down to roughly 100 meters.

The study utilized about 4 kilometers of buried fiber beneath University Park to observe how atmospheric acoustic energy couples into the ground and how Rayleigh waves can be resolved with high fidelity.

Models built from the data revealed four slow-velocity, weak zones beneath the campus, each 40–100 meters wide, consistent with voids, fractures, or fluids in karst geology and possibly linked to sinkhole susceptibility.

The work is contextualized within ongoing discussions of geophysical imaging, with the publication date and related Nature Portfolio items guiding broader methodological context.

Broader implications include improved geohazard assessment (sinkholes, landslides), groundwater and mineral/resource evaluation, and even planetary exploration where traditional seismic sources are scarce.

The study lists Penn State researchers Tieyuan Zhu and Nolan Roth as lead authors, with co-authors including Donggeon Kim, Rafał Czarny, Young Cheol Kim, and Christelle Wauthier.

The method could improve underground feature mapping in regions with low native seismic activity and limited access to conventional surveys.

Beyond Earth-based uses, the approach could support hazard mapping under urban areas and may extend to seismic surveys on other worlds with atmospheric phenomena similar to thunder, such as Titan.

Represented as a methodological advance in seismology and underground imaging, the work demonstrates how atmospheric energy can inform subsurface structure without traditional earthquakes.

Processing of recordings yielded about 309 virtual shot gathers from roughly 141,000 virtual shots, enabling near-surface seismic tomography to depths around 100 meters.

While promising for shallow hazard imaging in low-activity regions, the approach faces limits in extremely shallow sediments and higher-frequency resolution.