In order to check the relationship between ground-based electromagnetic anomaly and ionospheric effect before the famous Wenchuan M_S 8.0 earthquake, three physical models have been established to simulate the communication process of electromagnetic energy from the Wenchuan hypocenter to the Earth’s surface, via the atmosphere to the ionosphere to cause ionospheric variations.

A statistical method is tentatively utilized to study distribution properties of aftershocks of the Wenchuan sequence in the view of energy release. The results show that the events in the Wenchuan sequence are not independent but have mutual attraction, their spatio–temporal distribution tends to be nonrandom but definite and deterministic, and imply it is possible for energy release to be predicted, although we cannot accurately predict the occurrence time and locations of the imminent event.

The paper focuses on the enhancement of the electromagnetic signal in the waveguide between the surface of the Earth and ionosphere. The ionosphere can facilitate the electromagnetic wave propagation, as if the detectability of the observing system is improved effectively, which makes it reasonable that sometimes electromagnetic signals are recorded at a seemingly unreasonable distance.