The persistent ionospheric responses over Japan after the impact of the 2011 Tohoku earthquake

Multiple unusual ionospheric phenomena, such as ionospheric irregularities, nighttime medium-scale traveling ionospheric disturbances (MSTIDs), and planar traveling ionospheric disturbances (TIDs), were observed after the emergence of tsunami-induced concentric gravity waves.

The ionospheric irregularities initially developed over the Hokkaido region following the interference of gravity waves at similar to 8:45 UT. Remarkably, the Perkins-type nighttime MSTIDs accompanying the planar TIDs were discernible over Japan following the irregularities. By comparing with the tsunami model simulation and ocean buoy observations, it is determined that these planar TIDs, lasting for about 10 hr, were likely related to tsunami ocean waves reflected by seamounts, ridges, islands, and seafloor topography in the Pacific Ocean.