...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Pure and Applied Geophysics >Characterization of Fault Roughness at Various Scales: Implications of Three-Dimensional High Resolution Topography Measurements
【24h】

Characterization of Fault Roughness at Various Scales: Implications of Three-Dimensional High Resolution Topography Measurements

机译：不同尺度下的断层粗糙度表征：三维高分辨率地形测量的意义

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Accurate description of the topography of active fault surfaces represents an important geophysical issue because this topography is strongly related to the stress distribution along fault planes, and therefore to processes implicated in earthquake nucleation, propagation, and arrest. To date, due to technical limitations, studies of natural fault roughness either performed using laboratory or field profilometers, were obtained mainly from 1-D profiles. With the recent development of Light Detection And Ranging (LIDAR) apparatus, it is now possible to measure accurately the 3-D topography of rough surfaces with a comparable resolution in all directions, both at field and laboratory scales. In the present study, we have investigated the scaling properties including possible anisotropy properties of several outcrops of two natural fault surfaces (Vuache strike-slip fault, France, and Magnola normal fault, Italy) in limestones. At the field scale, digital elevation models of the fault roughness were obtained over surfaces of 0.25 m(2) to 600 m(2) with a height resolution ranging from 0.5 mm to 20 mm. At the laboratory scale, the 3-D geometry was measured on two slip planes, using a laser profilometer with a spatial resolution of 20 A mu m and a height resolution less than 1 A mu m. Several signal processing tools exist for analyzing the statistical properties of rough surfaces with self-affine properties. Among them we used six signal processing techniques: (i) the root-mean-squares correlation (RMS), (ii) the maximum-minimum height difference (MM), (iii) the correlation function (COR), (iv) the RMS correlation function (RMS-COR), (v) the Fourier power spectrum (FPS), and (vi) the wavelet power spectrum (WPS). To investigate quantitatively the reliability and accuracy of the different statistical methods, synthetic self-affine surfaces were generated with azimuthal variation of the scaling exponent, similar to that which is observed for natural fault surfaces. The accuracy of the signal processing techniques is assessed in terms of the difference between the "input" self-affine exponent used for the synthetic construction and the "output" exponent recovered by those different methods. Two kinds of biases have been identified: Artifacts inherent to data acquisition and intrinsic errors of the methods themselves. In the latter case, the statistical results of our parametric study provide a quantitative estimate of the dependence of the accuracy with system size and directional morphological anisotropy. Finally, based on this parametric study, we used the most reliable techniques (RMS-COR, FPS, WPS) to analyze field data. These three methods provide complementary results. The FPS and WPS methods determine a robust characterization of the fault surface roughness in the direction of striations and perpendicular to them. The RMS-COR method allows investigation of the azimuth dependence of the scaling exponent. For both field and laboratory data, the topography perpendicular to the slip direction displays a similar scaling exponent H-aSyen = 0.8. However, our analysis indicates that for the Magnola fault surface the scaling roughness exponent parallel to the mechanical striation is identical at large and small scales H-// = 0.6-0.7, whereas for the Vuache fault surface it is characterized by two different self-affine regimes at small and large scales. We interpret this cross-over length scale as a witness of different mechanical processes responsible for the creation of fault topography at different spatial scales.
机译：准确描述活动断层表面的地形是一个重要的地球物理问题，因为该地形与沿断层的应力分布密切相关，因此与涉及地震成核，传播和阻止的过程密切相关。迄今为止，由于技术限制，使用实验室或现场轮廓仪进行的自然断层粗糙度研究主要从一维剖面图获得。随着光探测与测距（LIDAR）设备的最新发展，现在可以在野外和实验室范围内在各个方向上以相当的分辨率精确测量粗糙表面的3D地形。在本研究中，我们研究了石灰岩中两个天然断层表面（法国的沃阿奇走滑断层和意大利的Magnola正断层）的几个露头的尺度性质，包括可能的各向异性。在现场范围内，在0.25 m（2）至600 m（2）的表面上获得了断层粗糙度的数字高程模型，其高度分辨率范围为0.5 mm至20 mm。在实验室规模下，使用激光轮廓仪在两个滑移面上测量3-D几何形状，该轮廓仪的空间分辨率为20 Aμm，高度分辨率小于1 Aμm。存在几种用于分析具有自仿射特性的粗糙表面的统计特性的信号处理工具。其中，我们使用了六种信号处理技术：（i）均方根相关（RMS），（ii）最大最小高度差（MM），（iii）相关函数（COR），（iv） RMS相关函数（RMS-COR），（v）傅立叶功率谱（FPS）和（vi）小波功率谱（WPS）。为了定量研究不同统计方法的可靠性和准确性，生成了具有比例缩放指数方​​位角变化的合成自仿射表面，与自然断层表面所观察到的相似。根据用于合成构造的“输入”自仿射指数与通过这些不同方法回收的“输出”指数之间的差异来评估信号处理技术的准确性。已经确定了两种偏差：数据获取固有的伪像和方法本身的固有误差。在后一种情况下，我们的参数研究的统计结果提供了对精度与系统大小和方向形态各向异性的依赖关系的定量估计。最后，基于此参数研究，我们使用了最可靠的技术（RMS-COR，FPS，WPS）来分析现场数据。这三种方法提供了互补的结果。 FPS和WPS方法确定了在条纹方向和垂直于条纹方向的断层表面粗糙度的鲁棒性。 RMS-COR方法允许研究缩放指数的方位角依赖性。对于现场和实验室数据，垂直于滑移方向的地形都显示类似的缩放指数H-aSyen = 0.8。然而，我们的分析表明，对于Magnola断层表面，与机械条纹平行的结垢粗糙度指数在大和小尺度H-// = 0.6-0.7时都是相同的，而对于Vuache断层表面，其特征是两个不同的自小型和大型仿射体制。我们将这种跨度长度尺度解释为负责在不同空间尺度上创建断层形貌的不同机械过程的见证。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号