Tsunamigenic ionospheric hole

Abstract

Traveling ionospheric disturbances generated by an epicentral ground/sea surface motion, ionospheric disturbances associated with Rayleigh‐waves as well as post‐seismic 4‐minute monoperiodic atmospheric resonances and other‐period atmospheric oscillations have been observed in large earthquakes. In addition, a giant tsunami after the subduction earthquake produces an ionospheric hole which is widely a sudden depletion of ionospheric total electron content (TEC) in the hundred kilometer scale and lasts for a few tens of minutes over the tsunami source area. The tsunamigenic ionospheric hole detected by the TEC measurement with Global Position System (GPS) was found in the 2011 M9.0 off the Pacific coast of Tohoku, the 2010 M8.8 Chile, and the 2004 M9.1 Sumatra earthquakes. This occurs because plasma is descending at the lower thermosphere where the recombination of ions and electrons is high through the meter‐scale downwelling of sea surface at the tsunami source area, and is highly depleted due to the chemical processes.

Two‐dimensional simulation of ionospheric variations in the vicinity of the epicenter of the Tohoku‐oki earthquake on 11 March 2011

“…[3] Another prominent phenomenon was significant TEC depletion near the epicenter Saito et al, 2011;Astafyeva et al, 2011;Heki, 2011;Kakinami et al, 2012]. Analyses of the TEC data indicate that TEC decreases suddenly at about 10 min after the onset of the earthquake and reaches the minimum in about 20 min accompanied with some wavy oscillations.…”

“…Analyses of the TEC data indicate that TEC decreases suddenly at about 10 min after the onset of the earthquake and reaches the minimum in about 20 min accompanied with some wavy oscillations. Kakinami et al [2012] examined the TEC data and concluded that the observed TEC depletion is due to descending motion of ionospheric plasmas at the lower thermosphere followed by the recombination of ions and electrons in the lower ionosphere. They suggested that the downwelling motion in the lower thermosphere is associated with the meter-scale downwelling of sea surface at the tsunami source area.…”

“…In the M9.0 Tohoku-oki earthquake on 11 March 2011, horizontal wavelike structures of TEC (total electron content) variations were detected by a dense GPS receiver network in Japan [e.g., Chen et al, 2011;Saito et al, 2011;Tsugawa et al, 2011;Astafyeva et al, 2011;Heki, 2011;Liu et al, 2011;Matsumura et al, 2011;Kakinami et al, 2012]. Those studies suggest that the acoustic-gravity waves generated by the sea surface uplift propagate upward to the ionospheric region, causing ionospheric oscillation, and that the center of the ionospheric wave source is located at about 100-150 km east or southeast of the epicenter.…”

Ionospheric characteristics prior to the greatest earthquake in recorded history

“…He also suggested that similar anomalies were seen in the 27 February 2010 Chile earthquake, and possibly in the 2004 Sumatra-Andaman and the 1994 HokkaidoToho-Oki earthquakes, but not in smaller earthquakes. However, an alternative interpretation of the TEC variation in the ionosphere associated with the 11 March 2011 Tohoku-Oki earthquake is given by Kamogawa and Kakinami (2013) on the basis of the work of Kakinami et al (2012). Their interpretation is that a tsunamigenic ionospheric hole, a wide depletion of the TEC, occurred after the co-seismic acoustic wave reached the ionosphere and gradually recovered at the normal state within several tens of minutes.…”

Changes of Ionospheric Total Electron Content Caused by Large-scale Earthquakes and Recent Earthquakes Occurred Around the Korean Peninsula

“…지진에서 발견됐던 지진 발생전 TEC의 비정상적인 증가는 사 실이 아니며, 쓰나미 이온 홀(tsunamigenic ionospheric hole, Kakinami et al (2012) (1) Leick, 2004).…”