Abstract: In this paper, based on study and application of some fuzzy mathematical methods and nonlinear science methods, and through practical test for earthquake prediction, some good medium term methods are deeply studied, and some good quantitative indexes have been picked up, such as seismic quietness anomaly μ_q, self-similarity subordinate functionμ_s,, boot strap statistical deviationσ_BM and others. Furthermore, the evolutionary features of seismicity pattern in late period of earthquake preparation are explored. The results show that, as quanti tative indexes for mid term prediction, μ_q,μ_s, and σ_BM can have obvious mid-term and short term changes before large earthquakes; the time series of spatial pattern can represent the general anomalous areas before earthquakes and the evolutionary features of the seismicity pattern.

Key words: Medium-term prediction, Quietness anomaly, Self-similarity subordinate function, Bootstrap statistical deviation