An approach to the validation of thermal and electromagnetic earthquake precursors: Effects of earth tides

It has been debated for years whether earth tides trigger earthquakes. A recent statistical study has proven the significance of earth tides in earthquake triggering. In this paper, we firstly show that large earthquakes in the region of the 2004 Sumatra earthquake (M9.0) occur largely during a specific phase of the Moon. Then, we show that the observed thermal/electromagnetic precursors of the outgoing long wave earth radiation and the VLF propagation anomaly (ionospheric perturbation) at the time of an earthquake are modulated by the tidal effect of the region. Finally, we propose a model to explain the observed behaviors of the thermal/electromagnetic precursors, and show that tidal stress can trigger earthquakes, leading also to thermal/electromagnetic signatures.

Research highlights► The aim of this research is to validate earthquake precursors by comparing behavior of earthquakes and that of earthquake precursors. ► The authors firstly show that large earthquakes in the region of the 2004 Sumatra earthquake (M9.0) occur largely during a specific phase of the Moon. ► Then, they show that the observed thermal/electromagnetic precursors of the outgoing long wave earth radiation and the VLF propagation anomaly (ionospheric perturbation) at the time of the earthquake are modulated by the tidal effect of the region also. ► Finally, they propose a model to explain the observed behaviors of the thermal/electromagnetic precursors, and show that tidal stress can trigger earthquakes, leading also to thermal/electromagnetic signatures.