Advanced Spatial Modeling on Distribution and Physical Property of Faults for Predicting Hydraulic Phenomena over Ultra-long Term

这项研究从以下四个方面描述了断裂对流体路径和地壳运动的作用：数据分析、样本测量和野外调查。分析使用了日本西部Kikuma和Toki花岗岩地区的岩面调查和深井钻探获得的断裂数据。提出了两种三维空间建模方法：非连续地质层和物性的OPTSIM和节理、断层等裂隙的GEOFRAC。OPTSIM采用机械最小化准则和随机模拟相结合的方法。GEOFRAC将裂缝数据的方向(走向和倾角)合并到模拟中。首先，裂缝位置是根据裂缝密度随机产生的。将裂缝方向转换为由7个二值变量组成的指标集，并利用主成分分析对这些变量进行压缩。然后使用克立格法估计这些主要…的分布更多的IPAL值。最后，根据模拟的位置和方向确定单元裂隙，并将角度和距离公差内的裂隙连接起来形成裂隙平面。GEOFRAC被证明能够描述一个可信的断层系统，因为模拟的方向与测量的方向很好地对应。此外，通过对地下温度分布的反演分析，计算了断裂带的区域导水系数。模拟了裂缝充填矿物的空间分布，确定了流体通过连续裂缝和断层的路径。将从多重阴影数字高程模型中检测到的线状结构作为大尺度断裂单元。利用模拟的连续裂缝和线形，识别出优势方向上的相似性和长度分布的直方图形状。通过对断裂带表层土壤中放射性核素的测量和分析，阐明了断层动力学和水力性质的部分非均质性。较少

This study has characterized the fault functions for fluid paths and crustal movements from the following four points of data analyses, sample measurements, and field surveys. The fracture data obtained by rock surface surveys and deep drillings at the Kikuma and Toki granite areas in west Japan were used for the analyses.1. Two 3D spatial modeling methods, OPTSIM for discontinuous geologic layers and physical properties and GEOFRAC for fractures including joints and faults, were developed. A mechanical minimization criterion and a stochastic simulation were combined for OPTSIM. GEOFRAC incorporates the directions(strikes and dips)of the fracture data into the simulation. At first, fracture locations are generated randomly following fracture densities. Fracture directions are transformed into an indicator set consisting of seven binary variables and the variables are compressed using the principal component analysis. Kriging is then employed to estimate the distributions of these princ … More ipal values. Finally, element fractures are determined from the simulated locations and directions, and the fractures within the angle and distance tolerances are connected to form a fracture plane. GEOFRAC was shown to be able to depict a plausible fault system because the simulated directions corresponded well to those measured. In addition, regional hydraulic conductivities of fault zone were calculated by an inversion analysis of the subsurface temperature distribution.2. Spatial distributions of filling minerals of fractures were modeled, which contributed to specify the fluid paths through continuous fractures and faults.3. Lineaments detected from multi-shaded Digital Elevation Model were used as large-scale fracture elements. Using the simulated continuous fractures and lineaments, similarity on the dominant directions and the histogram shapes of length distributions were identified.4. A part of heterogeneity in fault dynamics and hydraulic property were clarified through measuring and analyzing the radioactive nuclides in the top soils on fault zones. Less