Simulating brittle fault growth from linkage of preexisting structures
Simulating brittle fault growth from linkage of preexisting structures
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DOI：
10.1029/2007jb005388
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发表时间：
2008-07
影响因子：
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通讯作者：
R. Lunn;J. P. Willson;Z. Shipton;H. Moir
中科院分区：
文献类型：
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作者：
R. Lunn;J. P. Willson;Z. Shipton;H. Moir
许多研究人员提出了断层发育的概念性模型，这些模型基于孤立的断层、节理或矿脉等先前存在的构造之间的联系。到目前为止，这种模型主要使用理论力学来解释在连杆结构中观察到的详细的损伤区几何形状。本文首次利用断层破损区演化有限元模型MOPEDZ对几何复杂的断裂带构造的时空发展过程进行了数值模拟。模拟显示了一系列预先存在的节理(或断层)几何形状和应力条件下的空间和时间断裂带演化。模拟表明，连杆几何形状受三个关键因素控制：应力比；原始的关节几何形状，如收缩或伸缩配置；以及主应力的方向。模拟的连杆结构与现场观测的断裂带几何形状显示出密切的对应关系，所有二次和三次破坏特征都被再现。研究还表明，给定区域应力条件的信息，数值模拟可以用来预测断裂带的几何形状，从而识别最有可能(和最不可能)促进流体流动的构造。
Many researchers have proposed conceptual models of fault development that are based on the linkage of preexisting structures such as isolated faults, joints or veins. To date, such models largely use theoretical mechanics to explain the detailed damage zone geometries observed in linkage structures. In this paper, we present the first numerical simulations of the temporal and spatial development of geometrically complex fault linkage structures using the finite element model for fault damage zone evolution, MOPEDZ. Simulations show spatial and temporal fault zone evolution for a range of preexisting joint (or fault) geometries and stress conditions. Simulations show that linkage geometries are governed by three key factors: the stress ratio; the original joint geometry, such as contractional or dilational configurations; and the orientation of the principal stress. Simulated linkage structures display close correspondence to field observations of fault zone geometry, with all secondary and tertiary damage features being reproduced. The research also demonstrates that given information on the regional stress conditions, numerical modeling can be used to predict fault zone geometries, and hence, identify the most (and least) likely structures for promoting fluid flow.