The Hugin Fracture, discovered in 2011, is an approximately 3.5 km long seafloor fracture in the North Sea. This fracture was unexpected and, due to the geology in the North Sea no obvious explanation could be found. In our study, we adopt the hypothesis that the Hugin fracture was formed by differential compaction controlled by glacial load. We construct a simplified 2D geomechanical model partly covered by top load (ice sheet) and test this hypothesis. We employ transient poro-elastoplastic simulation with a finite element method. For the simulations, we had to make assumptions regarding the material properties, because the fracture is located in-between well locations. We used descriptions from drilling site survey reports and literature values and performed seismic matching form well paths to the Hugin Fracture. Nearby well data were only partly useful due to incomplete logging in the first 400 m below seafloor. To overcome this problem, we introduced a mixing k-value which allows us to easily change the material properties from pure clay to sand. Changing the mixing k-value for each simulation provided information about the limits and robustness of the simulation results. Simulation results show isotropic stress and strain distribution in the horizontally layered, isotropic part of the model that is totally covered by the ice. In the central, channelized part of the model a composite stress and strain pattern develops with sub-vertical focus areas tangential to channel edges. Low stress, strain and deformation values under total load increase drastically soon after the load starts to decrease, resulting in the development of fractures along the focussed zones. Surface deformation such as formation of compaction ridges above stiff clay-filled channels and depression associated with plastic deformation is observed. A fracture and associated surface deformation develop above the shallowest sand-filled channel, very much resembling the observed geometry at the Hugin Fracture. The simulation supports the formation hypothesis for the Hugin Fracture as a compaction fracture and suggests that thin ice sheets may induce differential compaction to a depth of several hundred meters.

2011年发现的Hugin断裂是北海约3.5公里长的海底断裂。该裂缝是意外的，由于北海的地质原因，没有发现明显的解释。在我们的研究中，我们采用这样的假说，即Hugin裂缝是由受冰荷载控制的压实差异形成的。我们构建了一个简化的2D地质力学模型，部分被顶部载荷（冰盖）覆盖，并测试了该假设。我们采用有限元方法进行瞬态孔隙弹塑性模拟。对于模拟，我们必须对材料特性做出假设，因为裂缝位于井口之间。我们使用了钻井现场勘测报告和文献资料中的描述，并通过地震路径匹配了到Hugin裂缝的井道。由于海床以下前400 m的测井不完全，附近的井数据仅部分有用。为了克服这个问题，我们引入了混合k值，使我们可以轻松地将材料属性从纯粘土更改为沙子。更改每个模拟的混合k值可提供有关模拟结果的极限和鲁棒性的信息。仿真结果表明，模型的水平分层各向同性部分中的各向同性应力和应变分布完全被冰覆盖。在模型的中央通道化部分中，形成了复合应力和应变模式，其次垂直焦点区域与通道边缘相切。负载开始降低后不久，总负载下的低应力，应变和变形值就会急剧增加，导致沿聚焦区域的裂缝发展。观察到表面变形，例如在刚性粘土填充通道上方形成压实脊和与塑性变形相关的凹陷。裂缝和相关的表面变形在最浅的填沙通道上方发展，非常类似于在休金断裂处观察到的几何形状。该模拟支持休金断裂为压实裂缝的地层假说，并表明薄薄的冰盖可能引起差异压实至数百米的深度。非常类似于在Hugin断裂中观察到的几何形状。该模拟支持休金断裂为压实裂缝的地层假说，并表明薄薄的冰盖可能引起差异压实至数百米的深度。非常类似于在Hugin断裂中观察到的几何形状。该模拟支持休金断裂为压实裂缝的地层假说，并表明薄薄的冰盖可能引起差异压实至数百米的深度。