Abstract: Many kings of values are used to express electromagnetic radiation information, but there is a common feature of quieting-intensifying-quieting before earthquake occurrence. Over ten years observational data from Langfang Electromagnetic Network in Hebei Province are used in this paper to better reflect this feature. The various weight values are given to Electromagnetic Radiation Information Values of various intensity sections, then the weight of every station is accumulated to reflect the intensity of the information amount in that day, and weight accumulation is integrated intermittently to express the anomaly duration. By analyzing four earthquakes (M_S≥5. 0) in supervising range, this method is found better in reflecting the short-term and impending anomaly feature before earthquake occurrence. Meanwhile the relation of the accumulated intensity, the duration with the earthquake and physical mechanism of the anomaly feature has been discussed.

Key words: Electromagnetic radiation, Information amount, Weight, Integral