The Fractal Dimension of Fault Gouges in the Gaoqiao Fault Zone
in the Three Gorges Dam Area
1 Key Laboratory of Earthquake Geodesy, Institute of Seismology, CEA, 40 Hongshance Road, Wuhan 430071, China
2 Wuhan Base of Institute of Crustal Dynamics, CEA, 40 Hongshance Road, Wuhan 430071, China
Abstract The Gaoqiao fault zone, which extends along the strike direction for more than 40 km, is a large-scale fault in the Three Gorges dam area. There were a series of seismic activities along the Gaoqiao fault zone before and after impoundment of the Three Gorges Reservoir. In this paper, the authors investigate the fractal dimension and mineralogy of the clay-rich fault gouge samples collected from the Gaoqiao fault zone based on grain size distribution and X-ray diffraction analysis. In this study, the main clay minerals of fault gouges are illite and chlorite, and the content of clay minerals is generally less than 35%, which is conducive to the stick-slip. The results demonstrate that the fractal dimension of fault gouges in the Gaoqiao fault zone range from 2.20 to 2.67, which indicates that the fault is essentially characterized by stick-slip. The mechanical properties of the fault and the fractal dimension of fault gouges show that it is divided into two segments. On the basis of the above, coupled with the analysis of seismicity, it is clear that we should pay attention to the moderate-sized earthquakes occurring on it in the future.
GAO Hongliang,YAO Yunsheng,WANG Qiuliang et al. The Fractal Dimension of Fault Gouges in the Gaoqiao Fault Zone
in the Three Gorges Dam Area[J]. jgg, 2015, 35(6): 963-968.
GAO Hongliang,YAO Yunsheng,WANG Qiuliang et al. The Fractal Dimension of Fault Gouges in the Gaoqiao Fault Zone
in the Three Gorges Dam Area[J]. jgg, 2015, 35(6): 963-968.