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Fractal size and spatial distributions of fault zones: An investigation into the seismic Chelungpu Fault, Taiwan
Author(s) -
Otsuki Kenshiro,
Uduki Takayuki,
Monzawa Nobuaki,
Tanaka Hidemi
Publication year - 2005
Publication title -
island arc
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.554
H-Index - 58
eISSN - 1440-1738
pISSN - 1038-4871
DOI - 10.1111/j.1440-1738.2004.00454.x
Subject(s) - geology , fractal , fractal dimension , slip (aerodynamics) , seismology , fault (geology) , instability , anisotropy , thickening , tectonics , geometry , mechanics , mathematics , physics , materials science , mathematical analysis , quantum mechanics , thermodynamics , polymer science
The fractality of fault zones of thickness T for the 248‐m‐long core from a borehole penetrating the northern segment of the seismic Chelungpu Fault, Taiwan, was analyzed. The frequency curve of T shows that the fractal dimension is normal when T is smaller than a characteristic thickness T c , and it becomes abnormally large when T exceeds T c . The fractal dimensions of size and spatial distributions of T increase as the mean distribution density of T increases, which is inconsistent with the evolution laws for ordinary brittle faults. This discrepancy implies that the thickening rate of T when T is more than T c is not constant, but a decreasing function of fault displacement. The slow thickening rate is related to the elastohydrodynamic lubrication which was effective on the fault when T exceeds T c . This slip instability mechanism can explain the large, fast and smooth slip on the northern segment of the Chelungpu Fault during the 1999 Chi‐Chi earthquake.