Despite over three-decades of active research and wide debate in the published literature, the mechanisms that govern the growth of polygonal faults are poorly understood. Here we investigate the growth of polygonal faults using a suite of geomechanical finite element forward models that couple dynamic fault propagation, sedimentation, and the mechanical compaction of unconsolidated granular sediment. We undertook a suite of numerical model simulations to explore the relationships between varying fault plane dip, residual friction of the fault, and the bulk material properties of the sedimentary sequence hosting the polygonal fault system. We find that the growth of polygonal faults within laterally-pinned sedimentary tiers can be explained by gravity-driven differential compaction and does not require additional causative elements to explain the gross pattern of strain accumulation. We also find that the magnitude of fault throw is influenced by the material properties and the original fault plane dip, but is most sensitive to the residual friction angle. Our models yield values for maximum throw versus height for the faults that fall within the range of global values compiled for polygonal faults, and throw rates are comparable to those recently measured in naturally occurring polygonal faults.

尽管在已发表的文献中进行了 30 多年的积极研究和广泛辩论，但对控制多边形断层生长的机制知之甚少。在这里，我们使用一套地质力学有限元正演模型来研究多边形断层的生长，该模型将动态断层传播、沉积和松散颗粒沉积物的机械压实相结合。我们进行了一套数值模型模拟，以探索不同的断层倾角、断层的残余摩擦力和多边形断层系统所在的沉积层序的大块物质特性之间的关系。我们发现，横向钉扎沉积层内多边形断层的生长可以通过重力驱动的差异压实来解释，并且不需要额外的成因元素来解释应变积累的总体模式。我们还发现断层倾角的大小受材料特性和原始断层面倾角的影响，但对残余摩擦角最为敏感。我们的模型产生的断层的最大抛距与高度值在为多边形断层编译的全局值范围内，抛掷率与最近在自然发生的多边形断层中测量的值相当。但对残余摩擦角最为敏感。我们的模型产生的断层的最大抛距与高度值在为多边形断层编译的全局值范围内，抛掷率与最近在自然发生的多边形断层中测量的值相当。但对残余摩擦角最为敏感。我们的模型产生的断层的最大抛距与高度值在为多边形断层编译的全局值范围内，抛掷率与最近在自然发生的多边形断层中测量的值相当。