Abstract:We use the empirical orthogonal function (EOF) analysis method to analyze the Kangding MS6.3 earthquake, the main mode and study period between the MS5.0 earthquake above the epicenter, and we discuss the physical meaning of the main mode. The results show that in the normal distribution fitting, there is agreater than 95% probability of accidental error of gravity observation data that is greater than 200 μGal of 7 phases of the Sichuan-Yunnan region. EOF analysis of the second model specification vector and the cumulative gravity changes have similar characteristics. The 6 earthquakes >MS6.0 during 2013 to 2014 and the second model specifications vector positive and negative conversion regions have more than 83.3% corresponding rate. This shows a long-term variation pattern in the gravity field. The first mode before and after the earthquake specification series is the coseismic signal, spatial similarity of 4 quadrant distribution and 4 earthquakes MS>6.0 in 2014 and the second mode vector specification of positive and negative conversion area of 100% corresponding rate, which indicates that the model of the region can represent short-term variations of the gravity model. EOF analysis method is used to study the temporal and spatial variations of the first mode and the normal vector of the Ganzi-Shimian section of the Kangding river before and after the Kangding MS6.3 earthquake. The results show that the distribution of the 4 quadrants of the specification values has already appeared in the latter half of the year. All the first mode results before the Kangding MS6.3 earthquake are included in this feature. According to the characteristics of the constant increase of the epicenter location, the change is from negative to positive before and after Kangding earthquake.
WEI Jin,HAO Hongtao,HU Mingzhang et al. Temporal and Spatial Distribution of Gravity Change before and after the Kangding MS6.3:Using the EOF Method[J]. jgg, 2017, 37(8): 864-869.