Econintersect: An upper atmospheric observation following the March 11, 2011 Sendai, Japan earthquake showed a clear signal that preceded the devastating Japanese tsunami by one hour. A group of 14 U.S. and French scientists and engineers have published their observation in Geophysical Research Letters. The group indicates that the observable signal from the ionosphere may be a new and reliable way to give advance warning that a tsunami has formed.From Geophysical Research Letters:
Although only centimeters in amplitude over the open ocean, tsunamis can generate appreciable wave amplitudes in the upper atmosphere, including the naturally occurring chemiluminescent airglow layers, due to the exponential decrease in density with altitude. Here, we present the first observation of the airglow tsunami signature, resulting from the 11 March 2011 Tohoku earthquake off the eastern coast of Japan. These images are taken using a wide‐angle camera system located at the top of the Haleakala Volcano on Maui, Hawaii. They are correlated with GPS measurements of the total electron content from Hawaii GPS stations and the Jason‐1 satellite. We find waves propagating in the airglow layer from the direction of the earthquake epicenter with a velocity that matches that of the ocean tsunami. The first ionospheric signature precedes the modeled ocean tsunami generated by the main shock by approximately one hour. These results demonstrate the utility of monitoring the Earth’s airglow layers for tsunami detection and early warning.
Econintersect wonders how variable the lead time will be for various circumstances from the ionosphere signal to the impact of a tsunami on the first shoreline. If the variability of time for all tsunamis proves to be small compared to the warning time, this process could be extremely valuable, not just for human life, but economically as well. Imagine how plans to maximize the value each person or business could save if the time before the tsunami hits was accurately known.
Sources: Geophysical Research Letters and R&D Mag
