THE PERSISTENT IONOSPHERIC RESPONSES OVER JAPAN AFTER THE IMPACT OF THE 2011 TOHOKU EARTHQUAKE

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Wednesday, September 11, 2019

Earthquake and tsunami are known to be the source of atmospheric gravity waves that can generate plasma ripples in the space. On March 11, 2011, a magnitude 9.0 earthquake occurred near the east coast of Honshu, Japan, unleashing a savage tsunami to strike offshore of Japan.

Graphic of two-dimensional filtered Global Navigation Satellite System (GNSS) total electron content (TEC) maps
Two-dimensional filtered Global Navigation Satellite System (GNSS) total electron content (TEC) maps derived from ground-based GNSS TEC observations with the Butterworth band-pass filtering (4–25 min) indicating the consecutive observations of ionospheric CTIDs, irregularity, tsunami TIDs, LSTIDs, and nighttime MSTIDs after the Tohoku earthquake on 11 March 2011.

The tsunami also triggered unprecedented concentric waves in space. We subsequently found two unusual ionospheric features related to Perkins-type ionospheric instability and planar waves over the Japan region. The Perkins-type ionospheric instability exhibits band structures and propagates southwestward in the northern hemisphere, which is often observed in solstice and solar minimum conditions. Electrodynamical coupling between Es and F layers is usually adopted to explain the fast growth of the band structures. The planar waves are most likely triggered by the reflected tsunami-induced gravity waves from the Pacific Ocean. Gravity waves can cause ionospheric instabilities, leading to the degradation of radio communication and satellite navigation systems. It is not very common to observe the nighttime MSTIDs in spring equinox. Due to the absence of Es layers, we suggest that the planar waves may contribute to the formation of scarce equinox nighttime MSTIDs. The results illustrate the vertical connection between the tsunami and space weather.

Publication Name: Space Weather
First HAO Author's Name: Nick Pedatella

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