Atmosphere-ionosphere response to the M9 Tohoku earthquake revealed by multi-instrument space-borne and ground observations: Preliminary results

Abstract

The recent M9 Tohoku Japan earthquake of March 11, 2011 was the largest recorded earthquake ever to hit this nation. We retrospectively analyzed the temporal and spatial variations of four different physical parameters -outgoing long wave radiation (OLR), GPS/TEC, Low-Earth orbit tomography and critical frequency foF2. These changes characterize the state of the atmosphere and ionosphere several days before the onset of this earthquake. Our first results show that on March 8 th a rapid increase of emitted infrared radiation was observed from the satellite data and an anomaly developed near the epicenter. The GPS/TEC data indicate an increase and variation in electron density reaching a maximum value on March 8. Starting on this day in the lower ionospheric there was also confirmed an abnormal TEC variation over the epicenter. From March 3-11 a large increase in electron concentration was recorded at all four Japanese ground based ionosondes, which return to normal after the main earthquake. We found a positive correlation between the atmospheric and ionospheric anomalies and the Tohoku earthquake. This study may lead to a better understanding of the response of the atmosphere /ionosphere to the Great Tohoku earthquake.

Ionospheric effects of earthquakes in Japan in March 2011 obtained from observations of lightning electromagnetic radio signals

“…4a in Akhoondzadeh (2012), we can see that in fact the growth of TEC started 8 days before the EQ, although the author suggests that the actual effect was observed only one day (3 days before the event), and the rest of the increase of TEC was associated with the solar and geomagnetic effects. Such a result of the increase of TEC in the interval of 6-10 March (with a peak on 8 March) was obtained in Ouzounov et al (2011). Besides, as follows from our results presented in Fig.…”

“…The analysis of the behavior of ionospheric parameters during the considered earthquake has been made in a number of papers, see for example (Ouzounov et al, 2011;Heki, 2011;Choi et al, 2011;Akhoondzadeh, 2012). Heki (2011) considered short-term precursors (about an hour before the EQ) in variations of the total electron content (TEC) in the ionosphere.…”

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

“…Ionospheric effects of the Tohoku earthquake are currently the subject of many papers. Above all, it is papers analyzing data from dense networks of GPS-receivers, located on the Asian territory (Akhoondzadeh, 2012;Kakinami et al, 2011;Astafyeva et al, 2013;Hao et al, 2012;Komjathy et al, 2012;Liu, 2012;Occhipinti et al, 2011;Ogawa et al, 2012;Ouzounov et al, 2011;Saito et al, 2011;Tsugawa et al, 2011) and data from the SuperDARN radar, located on the Hokkaido island (Nishitani et al, 2011;Ogawa et al, 2012). These instruments have the best temporal resolution -from several seconds to 2 minutes, enabling to monitor the highly dynamic processes.…”

Total Electron Content (TEC) Variations and Correlation with Seismic Activity over Japan

“…This data was provided by the National Oceanic and At-mospheric Administration's Space Physics Interactive Data Re-source (SPIDR) (http:// spidr.ionosonde.net/spidr/). This data was compared to other research (Hasbi et al, 2009) (Ouzounov et al, 2011) to determine whether any ionospheric irregularities could have been caused by solar or geomagnetic sources.…”