Earthquake-related gravity field changes at Beijing-Tangshan gravimetric network during 1987–1998

Abstract

Based on the 46 batch repeated observations of Beijing-Tangshan gravimetric network, the gravity field changes of the region during 1987–1998 have been determined. A comparison was made between the differences of these gravity field changes and the 8 reasonably large earthquake events (Mb≥ 4.0) in the region, showing the existence of the earthquake-related gravity field changes. It appears that there is usually a detectable change of a nearby gravity field well before an earthquake, followed by an opposite change afterwards.