On 12 May 2008 at 14:28 LT great earthquake (M=8.0) occurred at Wenchuan (31.00A degrees N, 103.40A degrees E), China. The hourly values of foF2 are analyzed over ten ionospheric observatories: Haikou (20.00A degrees N, 110.33A degrees E), Kunming (25.00A degrees N, 102.70A degrees E), Guangzhou (20.00A degrees N, 113.70A degrees E), Chongqing (29.50A degrees N, 106.40A degrees E), Lhasa (29.63A degrees N, 91.17A degrees E), Lanzhou (36.07A degrees N, 103.87A degrees E), Beijing (40.00A degrees N, 116.30A degrees E), Urumqi (43.75A degrees N, 87.63A degrees E), Chuangchun (43.83A degrees N, 125.30A degrees E) and Manzhouli (49.60A degrees N, 117.45A degrees E). With a new factor, effective sunspot number R(eff), the results show that there were giant positive disturbances of foF2 around the epicentral zone on 9 May, 3 days prior to the earthquake. Our results indicate that the observed positive ionospheric disturbances were most possibly associated with the imminent earthquake and the new analytic method has good prospects in practice.
Xu, T., Hu, Y., Wu, J., Wu, Z., Suo, Y., & Feng, J. (2010). Giant disturbance in the ionospheric F2 region prior to the M8.0 Wenchuan earthquake on 12 May 2008. Annales Geophysicae, 28(8), 1533–1538. https://doi.org/10.5194/angeo-28-1533-2010