Abstract: This paper studies the interval between two earthquakes, and points out that there exists an anomaly of h′ that has a limited time before a large earthquake. Usually, the earthquake occurs within the limited time. If the anomaly of h′ appears continuously, it is small but bigger than 1, that is a short-term anomaly. If one or more h′ anomaly appears, for example h′>4, even h′>9 and with bigger earthquakes (M≥4) nearby, it is usually an impending anomaly of local earthquake. Four earthquakes are used to examine the study and the result is satisfied. Finally, the information and disturbance are also studied.

Key words: Limited time, Impending earthquake prediction, Information, Disturbance, Short-term anomaly