Seismo-Tsunamigenic Ionospheric Hole Triggered by M 9.0 2011 off the Pacific Coast of Tohoku Earthquake

Abstract

Giant earthquake and tsunami widely disturbed ionospheric plasma via acoustic gravity waves. During the M 9.0 2011 off the Pacific coast of Tohoku earthquake, the ionospheric disturbances were generated by co-seismic epicentral ground/sea surface motion, Rayleigh-wave traveling, and tsunami-wave traveling. In addition, seismo-tsunamigenic ionospheric hole, widely sudden depression of ionospheric total electron content, was observed. The ionospheric hole gradually disappeared within roughly a few tens minutes.

Investigation of ionospheric response due to Tohoku earthquake using GPS satellite measurements

“…From the propagation velocities and periods of the VTEC oscillations shown in Table 1, two types of short period ionospheric disturbances were observed. The first type of ionospheric disturbance observed at stations nearer to the epicenter (0214, 0202 and 0191) has high amplitudes and average propagation velocity of 1212 m/s, which is in close agreement with the velocities (~1 km/s) observed by [6,8,12] for the same study area and the previous study [1] [3]. It is suggested that the VTEC oscillations of type 1 are caused by the collision interaction of the acoustic waves in the neutral atmosphere that are induced by the sudden uplift of the sea surface and charged particles in the ionosphere above the altitude of 100 km [13].…”

“…The previous study for the same event [6] observed that there are depressions for about 5 TECU and lasted after 40 minutes southwest from the epicenter but such long depression were not observed in the northeast direction as shown earlier in our result. While another study [12] have shown the direction is in northwestward.…”

“…Coseismic ionospheric disturbance (CID) of short periods were reported during the Sumatera-Andaman earthquake in 2004 [1][2][3], Tokachi-Oki earthquake in 2003 [4] and Tohoku earthquake [5,6]. This CID was observed about 11 minutes following large earthquakes and has periods of 4-5 minutes.…”

Tsunamigenic ionospheric hole

“…Besides traveling ionospheric disturbances generated by an epicentral ground/sea surface motion, ionospheric disturbances associated with Rayleigh‐waves as well as post‐seismic 4‐minutes monoperiodic atmospheric resonances and other‐period atmospheric oscillations [ Saito et al , 2011; Tsugawa et al , 2011; Rolland et al , 2011; Kamogawa et al , 2012], the ionospheric hole appears due to the tsunami induced by the subduction EQs. The tsunamigenic ionospheric hole is caused by the meter‐scale downwelling of the sea surface at the tsunami source area yields the hundred‐kilometer‐scale ionospheric plasma downwelling and plasma depletion due to the high recombination of plasma at the lower thermosphere through the chemical processes.…”

Ionospheric disturbances induced by a missile launched from North Korea on 12 December 2012

“…These data were obtained at Japan, Taiwan, and South Korea. The frequency of ionospheric disturbance seen in TEC variation in this event was slower than those observed after earthquakes [e.g., Calais and Bernard Minster, 1995;Choosakul et al, 2009;Kamogawa et al, 2012;Kakinami et al, 2013]. In the figure, the ionospheric point (IP) where the raypath from the GPS satellite pierced the ionosphere was assumed to be 425 km.…”