[S11-P] Poster

[S11-P-02] Possible conjugated TEC anomalies preceding large earthquakes

^○Liming He^{1, 2}, Kosuke Heki² (1.Northeastern University, Shenyang, China, 2.Hokkaido University, Sapporo, Japan)

Ionospheric total electron content (TEC) enhancement instantly before the very large earthquake was first found after the 2011 Mw9.0 Tohoku earthquake [Heki, 2011]. Up to now, the similar enhancements were observed before eighteen earthquakes with moment magnitude from 7.3 to 9.2 [Heki and Enomoto, 2015; He and Heki, submitted]. Recently, He and Heki [2016] analyzed the spatial distribution of preseismic ionospheric anomalies of three large earthquakes in Chile, i.e. the 2010 Maule (Mw8.8), the 2014 Iquique (Mw8.2), and the 2015 Illapel (Mw8.3) earthquakes, and obtained the three-dimensional structures of the TEC anomalies for the 2015 event based on a projection approach. The observation result showed that the epicenter, the positive and negative anomalies distribute along the field-aligned direction, which resembles the simulation scenario [Kuo et al., 2014]. Besides this near epicenter phenomenon, another expected effect is the possible mirror ionospheric TEC anomalies associated with the geomagnetic field, i.e. the TEC anomalies are probably observed at geomagnetic conjugate points meanwhile. Here, we performed a systematic search for the possible mirror image anomalies that are to emerge at geomagnetic conjugate points based on GNSS TEC observations.