Analysis of Gravity Variation and Vertical Crustal Deformation at Wuhan Jiufeng Seismic Station

  Objectives  Long period observation of gravity variation and crustal deformation is one of the important means to study the movement of underground material. However, long-term monitoring of regional material migration law is rarely carried out.

  Methods  Based on the absolute gravity and global navigation satellite system (GNSS) observation data of Wuhan Jiufeng seismic station from 2013 to 2020, we calculate the variation trend of long-period gravity and vertical crustal deformation. The linear fitting trend is carried out at the intervals of 1 year, 2 years and 3 years, and the annual change rate of absolute gravity, vertical crustal deformation and the corresponding ratio in different time periods are obtained.

  Results  The results show that the long-term gravity change rate of Wuhan Jiufeng seismic station is 0.479 9 μGal/a, the vertical crustal deformation is -1.2 mm/a, and the ratio is -0.399 9 μGal/mm. There is a certain deviation from the theoretical value, which may be related to the groundwater activities in this area. It is found that the data points are discretely distributed in different regions and close to the theoretical value.

  Conclusions  Through the study of the long-term trend of gravity change and crustal deformation and the distribution map of different periodic data, the process of underground material movement can be preliminarily judged, which provides an important reference for the interpretation of regional dynamic mechanism.