JGR Space Phys. https://doi.org/c2n2 (2019)

Changes in the ionosphere have been observed before earthquakes, which are thought to be caused by atmospheric perturbations around the earthquake’s epicentre from environmental changes of, for example, pressure or temperature. These perturbations are expected to propagate into the ionosphere, but no such atmospheric gravity waves have yet been observed. Now, Shih-Sian Yang and colleagues have studied the spatiotemporal evolution of atmospheric gravity waves in the stratosphere before an earthquake in Kumamoto, Japan, and found signatures of a causal relation.

Close to the epicentre’s location, the potential energy of the atmospheric gravity waves was significantly enhanced a week before the earthquake. At the same time, perturbations in the sub-ionosphere were observed. These findings hint at a correlation of atmospheric gravity waves in the ionosphere and the onset of an earthquake. Atmospheric observations might therefore serve as a future pre-warning system for earthquakes.