The ionospheric responses to the 2011 Tohoku, 2012 Haida Gwaii, and 2010 Chile tsunamis: Effects of tsunami orientation and observation geometry

We show the ionospheric signatures of the 28 October 2012 Haida Gwaii tsunami in both the total electron content (TEC) and the airglow layer. In addition, previously reported ionospheric signatures from the 11 March 2011 Tohoku and 27 February 2010 Chile tsunamis are reexplored in comparison to the newer Haida Gwaii detections. These events provide excellent test cases in the study of tsunami-ionospheric coupling efficiency, which is most notably affected by the observation geometry, tsunami propagation direction, and background ionospheric density. A simple calculation is developed that incorporates observation geometry to predict the relative coupling efficiency. The predictions are compared to the TEC observations and limitations are discussed.