Gravity variation before Kunlun mountain pass western M_s=8.1 earthquake

摘要

The relation between the gravity variation features and MS=8.1 earthquake in Qinghai-Xizang monitoring area is analyzed preliminarily, by using spatial dynamic variation results of regional gravity field from absolute gravity and relative gravity observation in 1998 and 2000. The results show that: 1) MS=8.1 earthquakein Kulun mountain pass western occurred in the gravity variation high gradient near gravity(s high negative variation; 2) The main tectonic deformation and energy accumulation before MS=8.1 earthquake are distributed at south side of the epicenter; 3) The range of gravity(s high negative variation at east of the MS=8.1 earthquake epicenter relatively coincides with that rupture region according to field geology investigation; 4) Gravity variation distribution in high negative value region is just consistent with the second shear strain(s high value region of strain field obtained from GPS observation.