Rigorous Evaluation of Gravity Change due to Crustal Vertical Deformation

The linear ratio relationship between the crustal vertical deformation and gravity change on the earth’s surface has been investigated in several studies. The crustal density change coupled with deformation, however, rarely has been included in previous models. In this study, we consider both single-layer and multilayer models for the crustal internal deformation to estimate the ratio between crustal vertical deformation and gravity change following the theory of coupling movement between crustal deformation and density change. The simulated results showed the following: (1) the gravity change that resulted from the vertical deformation of the whole crust could be calculated by the approximate gravity-to-height ratio coefficient when the deformation area was semi-infinite. When the deformation area was limited, the coupled motion equation should be used; otherwise an error on the µGal level could be introduced. (2) The results of the multilayer deformation model showed that the nonuniform crustal deformation produced gravity change, and the magnitude could reach µGal level, which could not be ignored. (3) The relationship between crustal vertical deformation and gravity change was not a simple linear ratio relationship. Whether we can use the approximate ratio coefficient to estimate gravity change needs to be considered in practical application. The simulation results in this paper had an important reference significance for understanding the relationship between crustal vertical deformation and gravity change. These results also could provide guidance for further study of the earth’s internal motion using the data of crustal deformation and gravity change.