Work Optimization Predicts Accretionary Faulting: An Integration of Physical and Numerical Experiments: Work Optimization Predicts Faulting
Work Optimization Predicts Accretionary Faulting: An Integration of Physical and Numerical Experiments: Work Optimization Predicts Faulting
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工作优化预测增生断层：物理和数值实验的结合：工作优化预测断层
DOI：
10.1002/2017jb013931
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Souloumiac, Pauline
中科院分区：
文献类型：
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作者：
McBeck, Jessica A.;Cooke, Michele L.;Herbert, Justin W.;Maillot, Bertrand;Souloumiac, Pauline
我们采用工作优化预测的几何形状的正面推力在两个阶段的不断发展的物理吸积实验。产生最大效率增益或每个新断层面积的外部功变化ΔWext/ΔA的断层被认为最有可能发展。预测的逆冲断层的几何形状匹配在1毫米内的观测位置和观测到的断层倾角的几度内，对于第一个前冲断层和后冲断层，当观测到的前冲断层是活跃的。产生大于最大ΔWext/Δ A的90%的第二逆冲断层和前冲断层的位置也与观测到的逆冲断层重叠。工作最佳断层倾角在使平均库仑应力最大化的断层倾角的几度之内。沿着滑脱层的滑动梯度产生局部升高的剪切应力和高应变能密度区域，这些区域促进滑脱层附近的推力启动。系统的机械效率（Wext）在每一个模拟阶段的断层和类似的实验力的演变。由于第一对相对于第二对的发展而导致的较高的ΔWext/Δ A表明，随着楔形物的发展，新推力的发展可能导致效率增益减小。断层传播所消耗的功的数值估计与从实验力数据和地壳断层计算的范围重叠。数值和物理实验的集成提供了一种强有力的方法，证明了工作优化预测故障发展的实用性。
We employ work optimization to predict the geometry of frontal thrusts at two stages of an evolving physical accretion experiment. Faults that produce the largest gains in efficiency, or change in external work per new fault area, ΔWext/ΔA, are considered most likely to develop. The predicted thrust geometry matches within 1 mm of the observed position and within a few degrees of the observed fault dip, for both the first forethrust and backthrust when the observed forethrust is active. The positions of the second backthrust and forethrust that produce >90% of the maximum ΔWext/ΔAalso overlap the observed thrusts. The work optimal fault dips are within a few degrees of the fault dips that maximize the average Coulomb stress. Slip gradients along the detachment produce local elevated shear stresses and high strain energy density regions that promote thrust initiation near the detachment. The mechanical efficiency (Wext) of the system decreases at each of the two simulated stages of faulting and resembles the evolution of experimental force. The higher ΔWext/ΔAdue to the development of the first pair relative to the second pair indicates that the development of new thrusts may lead to diminishing efficiency gains as the wedge evolves. The numerical estimates of work consumed by fault propagation overlap the range calculated from experimental force data and crustal faults. The integration of numerical and physical experiments provides a powerful approach that demonstrates the utility of work optimization to predict the development of faults.