Postseismic Vertical Deformation Following the 1990 Ms7.0 Gonghe Earthquake
详细信息
- 责任者：Hao Ming (State Key Laboratory of Earthquake Dynamics ; Institute of Geology ; China Earthquake Administration ; Beijing 100029 ; China) ; Shen Zhengkang
- 刊名：Acta Seismologica Sinica
- 出版年：2010
- 卷期：32(5)
- 关键词：大震 ; great earthquakes ; 地形变 ; ground deformation ; 青海 ; Qinghai Province
- 页码：p.557-569
- 图表：illus., 3 tables, 18 refs.
- 分类号：0500
- issnNo：ISSN0253-3782
- isbnNo：CN11-2021/P
摘要
By analyzing the leveling data observed one epoch before and six epochs after the quake across the coseismic fault, the authors find the following characteristics of the postseismic deformation: 1) the near field on the hanging-wall side of the coseismic rupture continued to uplift at large scale after the earthquake, with the highest rate measured in the first year; 2) the scope of postseismic uplifting region was larger than that of coseismic uplifting, but did not change during the postseismic deformation period; and 3) the time series of elevation change between two adjacent benchmarks can be modeled by a logarithmic relaxation function or an exponential relaxation function. In the paper, the authors also introduce a new method using leveling data and dislocation model in continuum to investigate the source and mechanism of postseismic deformation. The preliminary result suggests that two mechanisms operate simultaneously to produce the postseismic vertical deformation of the surface: (a) afterslip on the coseismic rupture fault plane of the main shock and its peripheral extensions,particularly upward to the sediment layer above the main rupture, and (b) viscoelastic relaxation of the lower crust and upper mantle, with a viscosity in the order of 1020 Pa·s.
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