Double resonance in seismo-lithosphere-atmosphere-ionosphere coupling

Investigations into causal mechanisms behind anomalous pre-earthquake phenomena are considered a promising way of earthquake prediction. Numerous promising channels for seismo-lithosphere-atmosphere-ionosphere coupling have been proposed; however, predicting earthquakes remains a great challenge in the scientific society. Short-period ground vibrations exhibiting frequency characteristics similar to natural frequencies caused by strata failure resonance have recently been detected using tiltmeters embedded in magnetometers prior to earthquakes. These vibrations originate from regions near the epicentres of forthcoming earthquakes and can be simultaneously detected by broadband seismometers and ground-based global navigation satellite system (GNSS) receivers. Unlike the total electron contents (TECs) obtained from orbiting satellites, the vibrations and the identifiable TEC perturbations in data from geostationary satellites of the BeiDou Navigation System share frequencies prior to earthquakes. However, the causal relationship between the vibrations and TEC perturbations remains unclear due to a gap in data observations between the lithosphere and ionosphere. To address this issue, an instrumental array was established to monitor vibrations and perturbations in the lithosphere, atmosphere, and ionosphere. Observational data from the array partially fill the gap, and analytical results show that ground vibrations, air pressure, magnetic fields, and TEC data shared a common frequency of approximately 5 × 10^–3 Hz (5 mHz) before major earthquakes. This suggests that the resonant ground vibrations trigger atmospheric resonance before earthquakes. Therefore, the double resonance (crustal and atmospheric resonance) model is a new explanation for the observed anomalies in multiple geophysical parameters in the lithosphere, atmosphere, and ionosphere. Retrieving resonant signals from multiple sources of observational data is a significant challenge, but once this issue is overcome, double resonance may contribute to practical earthquake prediction.