Power-law Distribution of Normal Fault Displacement and Length and Estimation of Extensional Strain due to Normal Faults
The Sierra de San Miguelito is a relatively uplifted area and is constituted by a large amount of silicic volcanic rocks with ages from middle to late Cenozoic. The normal faults of the Sierra de San Miguelito are Domino-style and nearly parallel. The cumulative length and displacement of the faults obey power-law distribution. The fractal dimension of the fault traces is -1.49. Using the multi-line one-dimensional sampling, the calculated exponent of cumulative fault displacements is -0.66. A cumulative curve combining measurements of all four sections yielded a slope of -0.63. The displacement-length plot shows a non-linear relationship and large dispersion of data. The large dispersion in the plot is mainly due to the fault linkage during faulting. An estimation of extensional strain due to the normal faults is ca. 0.1830.The bed extension strain is always less than or equal to the horizontal extension strain. The deformation in the Sierra de San Miguelito occurred near the surface, producing pervasive faults and many faults are too small to appear in maps and sections at common scales. The stretching produced by small faults reach ca. 33% of the total horizontal elongation.
作 者： XU Shunshan A.F.NIETO-SAMANIEGO S.A.ALANIZ-(A)LVAREZ 作者单位： XU Shunshan(Universidad Nacional Autónoma de México, Centro de geociencia, Apartado Postal 1-742,76001 Querétaro, Qro., Méxoco;Institute of Geomechnics, Chinese Academy of Geological Sciences, Beijing 100081, China)A.F.NIETO-SAMANIEGO,S.A.ALANIZ-(A)LVAREZ(Instituto Mexicano del Petróleo, Programa YNF, Eje Central L(a)zaro C(a)rdenas No.152, Col. San Bartolo Atepehuac(a)n, C.P. 07730, México, D.F., México)
刊 名： 地质学报(英文版) SCI 英文刊名： ACTA GEOLOGICA SINICA 年，卷(期)： 2005 79(1) 分类号： 关键词： power-law distribution normal faults small faults finite strain Mexico