How to catch a tsunami wave by monitoring the ionosphere

Edhah Munaibari

The current tsunami warning systems are limited in many ways. For example, they rely on detecting a preceding earthquake, which isn’t always the case (e.g., landslides), and the first direct measurement of the wave might take hours. A solution could come from studying the atmospheric gravity waves generated by the tsunami. Produced by the coupling of the ocean with the atmosphere, these internal (upward propagating) gravity waves accompany the open-ocean tsunami at the same speed (~1000 km/h). Also, they induce large fluctuations in the ionosphere’s electron content. They affect the electromagnetic signals emitted by the global navigation satellite system (GNSS) constellations, allowing us to track the imprint of the tsunami wave in the sky. As this approach relies on existing instrumentation, potentially doesn’t rely on detecting a preceding earthquake, and can track tsunami waves with a few minutes of time lag, it is a promising method to enhance existing tsunami warning systems.