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| Investigation of ionospheric TEC changes related to the 2008 Wenchuan earthquake based on statistic analysis and signal detection |
| Jianyong Li1, Guojie Meng1, Min Wang1, Hua Liao2, Xuhui Shen1 |
1 Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China
2 Earthquake Administration of Sichuan Province, Chengdu 610041, China |
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Abstract Ionospheric TEC (total electron content) time series are derived from GPS measurements at 13 stations around the epicenter of the 2008 Wenchuan earthquake. Defining anomaly bounds for a sliding window by quartile and 2-standard deviation of TEC values, this paper analyzed the characteristics of ionospheric changes before and after the destructive event. The Neyman-Pearson signal detection method is employed to compute the probabilities of TEC abnormalities. Result shows that one week before the Wenchuan earthquake, ionospheric TEC over the epicenter and its vicinities displays obvious abnormal disturbances, most of which are positive anomalies. The largest TEC abnormal changes appeared on May 9, three days prior to the seismic event. Signal detection shows that the largest possibility of TEC abnormity on May 9 is 50.74%, indicating that ionospheric abnormities three days before the main shock are likely related to the preparation process of the MS8.0 Wenchuan earthquake.
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Received: 06 July 2009
Published: 10 October 2009
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| Fund:the Key Technology Research and Development Program of China (2008BAC35B02) |
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Corresponding Authors:
Guojie Meng
E-mail: mgj@seis.ac.cn
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