RELATION OF GRAVITY ANOMALIES WITH FANXIAN M_L4.7 EARTHQUAKE OF HENAN PROVINCE

The variation of gravity field before and after Fanxian M_L4.7 earthquake, which occurred on Apr.9, 2006, is discussed.From September of 2005 to March of 2006 before the earthquake, the gravity field showed a decreasing tendency, but turned to fast increasing at March of 2006, and the earthquake occurred in the process of acceleration.The gravity values at parts of the sites and some segment showed some anomalies, with magnitude at 30~60×10^-8 m·s^-2.The gravity values did not recover after the earthquake.Variations of gravity field in this area may be caused by crustal deformation, quality transition in deep crust and fault creep.