ON EFFECTIVE RELAXATION TIME OF POSTSEISMICDEFORMATION IN EASTERN AND WESTERN CHINA
Hao Ming 1,2) ;Wang Qingliang 1) ; Zhan Wei 3) ;and Li Yuhang 1)
1)Second Crustal Monitoring and Application Center, Xi’an 710054;2)Institute of Geology, China Earthquake Administration, Beijing 100029;3)First Crustal Monitoring and Application Center, Tianjin 300180
Abstract：The postseismic deformation,observed by precise leveling,of Ms7.2 Xingtai earthquake in 1966, Ms7.8 Tangshan earthquake in 1976, Ms7.8 Tonghai earthquake in 1970, Ms7.6 Luhuo earthquake in 1973 and Ms7.0 Gonghe earthquake in 1990 each shows typical characteristics of decaying exponential. Considering both the effects of fault creep on the brittle creeping fault zone (BCFZ) and viscous flow below BCFZ,we estimate the effective relaxation time of the five great earthquakes with leastsquare method. The inversion results show that the difference of relaxation time between eastern and western China is very significant. The effective relaxation time of Tangshan earthquake is the longest (10.3 years), and the time of Xingtai earthquake is the second longest (4.4 years), while the effective relaxation time of Tonghai, Luhuo and Gonghe earthquake are about 2 years only. The significant difference may be caused by different upper crustal depth and viscosity of lower crust and upper mantle between eastern and western China.
Hao Ming,Wang Qingliang ,Zhan Wei et al. ON EFFECTIVE RELAXATION TIME OF POSTSEISMICDEFORMATION IN EASTERN AND WESTERN CHINA[J]. jgg, 2011, 31(6): 49-53.
