The Nonl inear Acceleration Regularity of the Large Seism During Seismic Active Period and the Trend Prediction of Large Seism for Future Three Years in Yunnan

On the basis of relation between the seism and solar activity, it is pointed out that the periodicity evolution of the seisimic activity is under the modulation of solar activity. The seismic activity has a cycle of 22 years besides the cycle of 11 years. Four active periods and four quiet periods of the seism have been formed from the 22 year cycle since this century. The interval between two large seisms seems to have at rend of gradually short time during a seismic active period in Yunnan. The regularity complies with an acceleration evolution of T_x=△T1/2>. The interval of the last large seism is even shorter than the prediction by this acceleration regularity in a seismic active period. If the eruptive date of a large seism is earlier than the date of prediction by this regularity for over 50%, then it indicates that this large seism will be last one in this seismic active period. According to the acceleration regularity the trend prediction of large seism for future three years in Yunnan is made in this paper.