摘要
This article briefly describes the abnormal variation of geomagnetic harmonic wave amplitude ratio before several earthquakes with MS≥7. The preliminary analysis shows that the characteristic of the long-term tendency anomaly of geomagnetic harmonic wave amplitude ratio of earthquakes with MS≥7 is the same as that of MS5~6 earthquakes. Most of the strong earthquakes occurred in the transition phase, restoring and rising phase, and the early phase of the restoring after geomagnetic harmonic wave amplitude ratio’s trend decrease. The anomaly before the earthquake usually lasted for more than 4 years, and the anomaly amplitude usually is more than0.10~0.20. The article also reviews the Wenchuan 8.0 earthquake’s forecasting process.