Abstract:In this study, we use gravity observation data from two stations in Lanzhou and Gaotai from 2011 to 2015. The MS6.6 earthquake, which occurred at the junction of Minxian and Zhangxian on July 22, 2013, is taken as the research object. The detrended fluctuation analysis method is used to deal with the continuous observation data of the two stations, and to try to extract anomaly information on gravity before the earthquake. The results show, with 9.4 times the standard deviation of the fractal index of the station as abnormal threshold, that there is a similar abnormal increase process before the earthquake on the gravity fractal index of the two stations. This indicates the gravity variation before the earthquake, has a continuous feature and shows a long-range correlation. This may be important information related to the earthquake. The study of this gravity fractal exponent is only preliminary and exploratory. Combined with the research results of other scholars, it is preliminarily speculated that this abnormal change may be related to the material migration in the middle and lower crust and even the upper mantle.
XU Kangsheng,LI Ying,ZHANG Weidong. The Anomaly of Fractal Exponent on Gravity before the Minxian-Zhangxian MS6.6 Earthquake[J]. jgg, 2019, 39(7): 743-746.