Abstract: In 1999, the author published results of mid-long term forecast for the 2008 Wenchuan M_S8.0 earthquake. The forecasted riskest area were Wenchuan county, with the upper limit magnitude of 7.2, and the risk periods of time had benn estimated to be 2007—2012 and beyond 2021. This paper expounds synopsis and characteristiucs of mi-long term forecast method by using the superpositive field of residual and present stresses, advances improving on the forecast, and explores a short term forecast method following the tracks of mid-long term forecast for the 2008 Wenchuan M_S8.0 earthquake.

Key words: Wenchuan M_S8.0 earthquake, Mid-long term forecast, Short term forecast method