Abstract:Based on mobile gravity observation data from Leiqiong area since 2016, we process the joint observation data in the second half of 2017 by using different adjustment methods. The Zhanjiang and Qiongzhong absolute gravity points are considered as the spatial reference of the Leiqiong survey network, and we study the dynamic changes of gravity field in Leiqiong area since 2016. We focus on the differential and cumulative dynamic changes of regional gravity fields before the 2018-03-20 Yangjiang M4.2, the 2019-03-05 Leizhou M4.1, the 2019-08-20 Sanya M4.2, and the 2019-10-12 Beiliu M5.2 earthquakes. The results show that there are abnormal changes in the gravity field near the epicenter before the earthquakes, except the Leizhou M4.1 earthquake. The results of this study indicate that the regional gravity field may reflect a certain preseismic anomalous of magnitude 4~5 earthquakes with reasonably dense observation networks and proper data processing methods.