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Pre-earthquake ionospheric anomalies registered by continuous GPS TEC measurements

2004; Copernicus Publications; Volume: 22; Issue: 5 Linguagem: Inglês

10.5194/angeo-22-1585-2004

1432-0576

J. Y. Liu, Yu-Jung Chuo, S. Shan, Y. B. Tsai, Y. I. Chen, С. А. Пулинец, Shui Yu,

Seismology and Earthquake Studies

Abstract. In this paper we examine pre-earthquake ionospheric anomalies by the total electron content (TEC) derived from a ground-based receiver of the Global Positioning System (GPS). A 15-day running median of the TEC and the associated inter-quartile range (IQR) are utilized as a reference for identifying abnormal signals during all of the 20M≥6.0 earthquakes in the Taiwan area from September 1999 to December 2002. Results show that the pre-earthquake ionospheric anomalies appear during 18:00–22:00LT (LT=UT+8h) within 5 days prior to 16 of the 20M≥6.0 earthquakes. This success rate of 80% (=16/20%) suggests that the GPS TEC is useful to register pre-earthquake ionospheric anomalies appearing before large earthquakes. Key words. Ionosphere (ionospheric disturbances; ionosphere-atmosphere interactions)