Abstract: In early October 1997, based on the obviously high value anomalies in the middle part of Inner Mongolia and the northern part of North China in the result of spatial and time scanning of the seismic inhomogeneous degree (the CL value method) all over China, it was proposed that there might happen an earthquake with M = 5~6 respectively in each region in the com­ing year. Since then, an Ms 5. 0 earthquake and an Ms 6. 2 earthquake happened in these two regions respectively. In this paper, the change processes of the CL values before the two events are discussed and the change features of the CL values before moderately strong earthquakes are concluded preliminarily to apply this method to the prediction of moderately strong earth­quakes more broadly in the future.

Key words: CL value method, Moderately strong earthquake, Change feature