Abstract: Mobile regional gravity measurement is one of the most important means in earthquake monitoring, and the observed micro-gravity changes can reflect the density anomalies of the deep crust, forming process of crustal structure and earthquake. Gravity changes before earthquakes have been widely reported. How to optimize the observation system, and identify gravity change signals, which is in the potential inner crust and within the depth range of earthquake preparation are very important problems. By using numerical model test, we present different gravity changes and features of these anomalies from different field-source parameters, and analyze gravity changes and gravity gradient changes with different parameter models. We also conclude that gravity gradient is more sensitive to the boundary of abnormal body, and compared with gravity, it is more efficient to identify the shallow anomalies and more easier to outline the boundary of abnormal body. With the putting forward of optimization scheme of the observation system and the increasing of observation accuracy, we can further combine it to the “equivalent source” to infer the sources of the field, and analyze the dynamical feature of seismogenic zone.

Key words: Micro-gravity changes, Vertical gravity gradient changes, Field-source parameter, Equivalent source