Abstract: Based on earthquake Cases in China and relative literature data, by collecting fluid anomalous information before moderate-strong earthquakes in Liaoning and surrounding area, we analyzed anomalous fluid characteristics before the moderate earthquakes, and set up a fluid index system for Liaoning area. The analysis shows that the precursory anomaly of M≥7 earthquakes have characteristics of spatial distribution, multi-abnormalities number, long duration, large varied amplitude and synchronously. The earthquakes mainly occurred with sudden jump and increases of anomalous fluid, and usually in the transition time of decreased anomalous frequency. At the same time, the number of the macroscopic anomaly can reached thousands of times, and have significant characteristics of spatial distribution. The precursory anomalies of earthquakes with M5~6 are mainly concentrated in the range of 200 km, and have relatively short duration. Besides, the water radon anomalies take an important role in anomalous fluid. M5~6 as well as M≥7.0, usually happened 1~2 month after the transition decreases of anomalous frequency, and there is less or no macroscopic anomalies for M5~6 earthquakes.

Key words: Anomalous Fluid, Earthquake case, Prediction index, Liaoning region