A tsunami propagating in open ocean can produce gravity waves and thus perturb the ionosphere. In this study,we employ a second-order numerical differencemethod using GPS total electron content observed in New Zealand to detect the ionospheric disturbances triggered by the Chile tsunami that occurred on 1 April 2014. We observe traveling ionospheric disturbances (TIDs), which have similar horizontal velocity and direction as the tsunami waves, at different times after the event. According to the arrival times, the latter TIDs (about 14.5–15 h after earthquake) can be attributed to the tsunami waves whereas the former one (about 12 h 30 min after earthquake) could be related to other sources. This suggests that besides the propagation velocity and direction, the arrival time is also necessary to distinguish tsunami-driven TIDs correctly. Furthermore, we observe the phenomenon that the detected tsunami-driven TIDs are superimposed upon other nontsunami-driven ionospheric perturbations far away fromthe epicenter. The superimposed TIDs eventually separate due to their different propagation velocities.
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