Abstract: Based on the records of the earthquake cases since 1966 in Earthquake Cases in China, according to the anomaly items and change types, we get the statistical correlation associated with subsurface fluid abnormities between the quantity and magnitude, epicentral distance and the duration. The results show that, in mainland China, the numbers of abnormal underground fluid events before earthquakes of M<6.5 has no correlation with the magnitude, and the number increases with magnitude if M>6.5, and they grow exponentially; Subsurface fluid abnormities are more concentrated in the range of 300 km from the epicenter, and no significant difference between each measurement, and abnormities number assumes the Gamma distribution characteristics with epicentral distance. The space-time features of subsurface fluid abnormities are mainly in three typical types, ‘shrink to the epicenter’, ‘tectonic control’ and ‘concentricity’. Abnormly amount consists of two typical types before the earthquake, ‘sustained growth’ and ‘decrease after increase first’, and the latter had more. The statistical characteristics of underground fluid precursor information in this paper can provide references for the future practice of earthquake prediction.

Key words: Subsurface fluid precursors, Statistical characteristics, Earthquake Cases in China