Is there a one-to-one correspondence between ionospheric anomalies and large earthquakes along Longmenshan faults?

On 12 May 2008, a destructive M8.0 earthquake
struck Wenchuan County (31.0 N, 103.4E) in the Longmenshan fault zone of southwestern China. Five years later, on 20 April 2013, another terrible M7.0 earthquake struck
Lushan County (30.3 N, 103.0 E) in the same fault area, only 87 km away from the epicenter of the Wenchuan earthquake.
In this paper, an integrated wavelet analysis methodology is proposed to detect and diagnose ionospheric total electron
content (TEC) anomalies related to seismic activities.
Analytic wavelet transform is used to detect ionospheric perturbations, and then cross-wavelet analysis is used to diagnose
ionospheric anomalies by gaining further insights into the dynamic relationship between the anomaly variability of
ionospheric TEC and geomagnetic indices for the same set of observations. The results show that a significant ionospheric
disturbance occurred on 9 May 2008 above the forthcoming epicenter, 3 days prior to the Wenchuan earthquake. However,we did not observe an ionospheric anomaly over the
epicenter of the Ya’an earthquake during the 1 month period before the shock. Finally, we discuss the possible interpretations of the different seismo-ionospheric effects for the two similar earthquakes.

National Important Basic Research Project (Grant No. 2011CB707102), National Natural Science Foundation of China (Grant No.41104104), and the Fundamental Research Funds for the Central Universities (Grant No. N120801001)

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