Abstract: A new norm, Cr value which could mirror the seism ogenic process entering the mid-short term phase, is proposed by the analysis of the seismicities with a certain magnitude level occurring several years prior to strong earthquakes. It could reflect the state around the peak point of the constitutiv erelation curve. The results of seven earthquake cases with magnitude about 7 show that the Cr value is unusually high before the earthquakes. These strong earthquakes occurred 1~3 years after the maximum value of Cr emerged, and most about 1 year. It will be beneficial to the mid-short term earthquake prediction.

Key words: Mid-short term prediction, Strong earthquakes with magnitude of about 7, The Cr value