Abstract:Based on flow gravity observation data from 2011 to 2013 in southern Liaoning province, in-depth analysis is carried out on the evolution characteristics and the mechanism of gravity space before the M5.1 Dengta earthquake in 2013. The study shows that: 1) There is a good correspondence in time and space between the anomaly of the gravity field and the M5.1 Dengta earthquake in middle south Liaoning province. 2) One year before the earthquake, the characteristics of the four quadrants are apparent, half a year before the earthquake, 50 μGal reverse change appeared, accompanied by high gradient zone of gravity change; the rising and falling trend of the gravity point value sequence are obvious, and the gravity profile fluctuates intensely. 3) Combining the background field of gravity change and the regional geological structure in 2011 to 2012, we infer that this earthquake may be a result of the density variation of the deep material and tectonic movement in the southern region of Liaoning.