Along-strike variations of the slip direction on normal faults : Insights from three-dimensional finite-element models
Along-strike variations of the slip direction on normal faults : Insights from three-dimensional finite-element models
复制标题
正断层上滑动方向的沿走向变化：来自三维有限元模型的见解
DOI：
10.1016/j.jsg.2007.10.002
复制
发表时间：
2008
影响因子：
3.1
通讯作者：
A. Hampel
中科院分区：
文献类型：
--
作者：
G. Maniatis;A. Hampel
自然界中的正断层表现出滑动方向沿着走向的系统变化，在其中心为纯倾滑，在其端部附近逐渐变为斜滑。在这里，我们评估的变化的滑动方向沿着正断层的三维有限元模拟。模型结果表明，在从断层中心到其尖端的距离的三分之二以上，走滑分量几乎线性增加，这导致沿沿着走向的滑动矢量的增加。不包括断层尖端，横向滑动和断层长度之间的关系可以近似为幂律函数，这表明走滑分量与倾滑和断层倾角成正比。左旋和右旋滑动分量的发育是由下盘和上盘最小主应力方向向断层中心偏转引起的。在亚平宁山脉中部，意大利，两个故障的比较，显示出良好的协议之间的模拟和测量的滑动矢量。收敛滑动模式的发生意味着，谨慎的建议时，推断斜向延伸，区域应力轨迹和古应力场的滑动矢量测量远离故障中心。
Normal faults in nature exhibit a systematic variation of the slip direction along strike, with pure dip-slip at their centres that changes gradually to oblique slip near their tips. Here we evaluate the variation of the slip direction along normal faults by three-dimensional finite-element modelling. The model results reveal a nearly linear increase of the strike-slip component over two-thirds of the distance from the fault centre to its tips, which results in an increasing obliqueness of the slip vector along strike. Excluding the fault tips, the relationship between lateral slip and fault length can be approximated by a power-law function, which shows that the strike-slip component is proportional to the dip-slip and to the fault dip. The development of the sinistral and dextral slip components is caused by the orientation of the minimum principal stress, which is deflected toward the fault centre in both footwall and hanging wall. A comparison with two faults in the Central Apennines, Italy, shows good agreement between modelled and measured slip vectors. The occurrence of converging slip patterns implies that caution is advised when inferring oblique extension, regional stress trajectories and palaeostress fields from slip vectors measured away from the fault centre.