Seismo-traveling ionospheric disturbances of ionograms observed during the 2011 M w 9.0 Tohoku Earthquake

Abstract

In this paper, sequences of ionograms recorded by 4 ionosondes in Japan and 1 in Taiwan are employed to examine seismo traveling ionospheric disturbances (STIDs) triggered by the 11 March, 2011, M 9.0 Tohoku Earthquake. The circle method, a standard/traditional technique of seismologists for locating an earthquake, is used to find the origin and compute the propagation speed of the triggered STID. Results show that the STID speeds induced by Rayleigh waves, acoustic gravity waves mainly traveling in the ionosphere, and tsunami waves of the Tohoku Earthquake are 2100-3200 m/s (2.1-3.2 km/s), 900 m/s, and 200 m/s (720 km/hr), respectively. The origins derived by the circle method near the epicenter confirm that the observed STIDs were triggered by the seismic waves and tsunami waves of the Tohoku Earthquake.

The resonant response of the ionosphere imaged after the 2011 off the Pacific coast of Tohoku Earthquake

“…Its propagation speed was estimated to be ∼225 m/s and frequency of about 1.8 mHz. These features are coherent with the observations of Maruyama et al (2011) and Tsai et al (2011) using GPS-TEC technique and the observations of Liu and Sun (2011) in ionogram records. They are corroborated here by normal modes computation.…”

Dynamics of vertical ionospheric inhomogeneities over Irkutsk during 06:00–06:20UT 11/03/2011 caused by Tohoku earthquake

“…Similar effect was seen in Japan and Taiwan (Liu and Sun, 2011), but at larger distances the effect apparently was not detected. For a detailed analysis and testing of analysis techniques, we chose 06:15UT ionogram with typical distortions caused by an earthquake (Fig.3A).…”

“…Relationship of these irregularities with the earthquake can be substantiated by observations of the similar irregularities after the earthquake in relative proximity to the epicenter Liu and Sun, 2011).…”

“…These structures were very dynamic (Liu and Sun, 2011;Maruyama et al, 2011). However, traditionally ionosondes have relatively low (about 15 minutes) temporal resolution, not allowing us to study dynamics of the vertical structure of irregularities.…”

Ionospheric Precursors Observed in TEC Due to Earthquake of Tamenglong on 3 January 2016

“…Namgaladze 9 considered E  B drift to be the most likely physical mechanism responsible for the seismoionospheric anomaly formation. Based on ground-based measurements, a significant decrease of the ionospheric electron density, foF2 and TEC simultaneously were observed 1-4 days before the Chi-Chi, Rei-Li and Chia-Yi earthquakes 2,10,11 . Recently, a case study and statistical analysis were made to observe pre-seismic anomalies in TEC 5,[12][13][14] .…”