[M-IS10] Interdisciplinary studies on pre-earthquake processes

[MIS10-P02] Singular Spectrum Analysis of the Total Electron Content Changes Prior to M>6.0 Earthquakes in the Chinese Mainland

*Hongyan Chen¹、Miao Miao¹、Ying Chang²、Qiao Wang³、Xuhui Shen³、Katsumi Hattori^4,5、Peng Han¹ (1.Southern University of Science and Technology, Shenzhen, China、2.Institute of Mining Engineering, BGRIMM Technology Group, Beijing, China、3.National Institute of Natural Hazards, Ministry of Emergency Management of China, Beijing, China、4.Graduate School of Science, Chiba University, Chiba, Japan、5.Center for Environmental Remote Sensing, Chiba University, Chiba, Japan)

キーワード： total electronic content, earthquake, singular spectrum analysis, ionospheric anomaly

Early studies have shown evidence of the seismo-ionospheric perturbations prior to large earthquakes. Due to dynamic complexity in the ionosphere, the identifification of precursory ionospheric changes is quite challenging. In this study, we analyze the total electron content (TEC) in the global ionosphere map and investigate the TEC changes prior to M > 6.0 earthquakes in the Chinese Mainland during 1998–2013 to identify possible seismo-ionospheric precursors. Singular spectrum analysis is applied to extract the trend and periodic variations including diurnal and semi-diurnal components, which are dominated by solar activities. The residual TEC which is mainly composed of errors and possible perturbations induced by earthquakes and geomagnetic activities is further investigated, and the root-mean-square error is employed to detect anomalous changes. The F10.7 and Dst index is also used as criterion to rule out the anomalies when intense solar or geomagnetic activities occur. Our results are consistent with those of previous studies. It is confifirmed that the negative anomalies are dominant 1–5 days before the earthquakes at the fifixed point (35°N, 90°E) during 0600–1000 LT. The anomalies are more obvious near the epicenter area. The singular spectrum analysis method help to establish a more reliable variation background of TEC and thus may improve the identifification of precursory ionospheric changes.