Seismic Observations from Two Long-Track EF4 Tornadoes in the Central United States

Abstract Tornadoes present a significant hazard to life and infrastructure, yet reliably detecting tornadoes remains challenging. Seismic monitoring has the potential to enhance tornado detection by recording seismic waves induced by tornadoes. We investigated tornado seismic signals associated with two EF4 tornadoes in the central United States: the May 2025 Somerset-London, Kentucky, tornado and the December 2021 tri-state tornado, each of which passed within 2 km of a broadband seismometer. We analyzed seismic data in conjunction with radar reflectivity and tornado track information to characterize seismic energy during each tornado’s passage. For one of the tornadoes, we also interpreted data from barometric pressure and infrasonic sensors collocated with the seismometer. Seismograms, spectrograms, and power spectral densities (PSDs) were evaluated within specific tornado and nontornado windows to isolate tornadic signals. Seismic amplitudes increased across a broad range of frequencies from 0.005 to 45 Hz during the passages of each tornado and from storm-related gust fronts. Tornadoes and gust fronts both induced low-frequency (0.005–0.01 Hz) signals that we attribute to tilt, which indicates that this signal alone is not diagnostic of tornado presence. In contrast, PSDs for all components in the 0.5–10 Hz band were consistently elevated during the tornadoes’ passages relative to nontornado scenarios for both events. The enhanced broadband seismic response was confined to periods when the tornadoes were less than ∼15 km from the stations, indicating a possible distance-based detection threshold. These results indicate the potential for seismic observations to complement existing tornado detection strategies.