Imaging Earth’s subsurface with thunderstorm-generated seismic waves

Abstract

Thunder generates atmospheric acoustic waves that couple into the ground, producing seismic signals called “thunderquakes.” Although widely observed, this atmosphere-solid Earth conversion has rarely been exploited for imaging because the coupled wavefield is complex and its governing physics are poorly constrained. Here, we show that thunderquakes recorded by preexisting telecommunication fiber-optic cables using distributed acoustic sensing (DAS) contain coherent air-coupled Rayleigh waves that can serve as seismic energy sources for near-surface tomography. We validate this mechanism using three-dimensional spectral-element simulations and dispersion modeling of thunderquakes. We analyze 2.5 years of continuous DAS data and a catalog of 458 high-fidelity thunderquakes validated by lightning records. Cross-correlation virtual-source interferometry and stacking yield dispersed surface waves from which we invert shear-wave velocity structure to ∼100-meter-depth beneath an urban karst setting. The resulting tomographic image reveals several previously undetected weak zones, some coinciding with surface deformation measured by Interferometric Synthetic Aperture Radar. The tomographic results are further validated by independent borehole logs and engineering surveys. Our results establish that thunder energy can be converted into dispersive seismic wavefields in the solid Earth and that thunderquakes can act as novel, meteorologically driven sources for seismic imaging in regions with limited access to traditional seismic sources.