Modelling tsunami induced coarse clast transport , combination of physical experiments, advanced numerical modelling and field observations

虽然沿海地区对人口和工业极具吸引力，但它们也极易受到极端海浪事件(海啸、风暴潮)的影响。考虑到预期的人口和工业持续增长，迫切需要高精度地评估频率-震级关系和潜在损害。在这种评估的基础上，有可能制定危险管理计划和减灾战略。即使高强度的海啸可能造成灾难性的影响，但其重复发生的时间间隔在数百年到数千年之间。因此，在历史记录较短的特定海岸，可能没有对这种最坏情况的观测，甚至没有测量结果。在这种情况下，岸上沉积的海洋沉积物为极端洪水事件提供了证据。通过将特定的泥沙特性与颗粒运动所需的波能联系起来，可以得出引起泥沙运动(海啸或风暴潮/波浪建立)的水动力过程的明显特征。由于水下地块和巨石作为细微沉积物更能抵抗侵蚀和人类影响，它们更适合进行此类调查。然而，在大多数情况下，区分风暴和海啸是一项艰巨的任务。数值模型可以支持这样的解释，但仍然存在几个简化问题，如忽略沉积载荷、多个巨石之间的相互作用或复杂的巨石形状。此外，这些因素在最先进的物理实验室实验中也被忽略了。同样，只有在均匀形状的水深和海岸地形上利用理想化形状的人体模型进行的实验是已知的。拟议的项目旨在弥合最先进的四个重大差距。首先，将通过实验室实验来分析和比较(I)复杂的和理想化的模型巨石的行为以及(Ii)它们之间在海啸抬高期间的相互作用。随后研究了(Iii)不均匀的测深设置和(Iv)沉积载荷对巨石运输方式、路径和距离的影响。下一步包括利用物理实验的结果来开发、校准和验证数值两相模型。基于摄影技术记录和数字实施的地形和块体沉积数据，该模型应能够在项目结束时以前所未有的精度模拟海啸引发的运输事件。对于项目后的未来，模型应用计划用于博内尔岛(荷属安的列斯群岛)，那里的沿海巨石沉积学已经有了非常详细的记录。

While coastal areas are highly attractive for population and industry, they are also highly exposed to extreme-wave events (tsunamis, storm surges). Considering the expected continuing population and industrial growth, there is an urgent need to assess frequency-magnitude relationships and damage potentials with high accuracy. Based on such assessments, it is possible to develop hazard management plans and hazard-mitigation strategies. Even though high-magnitude tsunamis may cause disastrous impacts, their recurrence intervals are in the range of hundreds to thousand years. Thus, at particular coasts with short historical records, no observations or even measurements of such worst-case scenarios might be available. In this case marine sediments deposited onshore provide, evidence for an extreme-flooding event. By associating specific sediment characteristics with the necessary wave-energy for particle movements, distinct characteristics of the hydrodynamic process inducing the sediment transport (tsunami or storm surge/wave setup-up) can be derived. Since subaerial blocks and boulders are more resistant towards erosion and human impact as fine sediments, they are more suitable for such investigations. However, distinguishing between storm and tsunamis is in most cases a tough task. Numerical models can support such interpretations, but still suffer from several simplifications as negligence of sedimentary load, interactions between multiple boulders or complex boulder shapes. Furthermore, these factors are also neglected in state-of-the-art physical laboratory experiments. Likewise, only experiments utilizing idealised shaped body-models on uniform shaped bathymetries and coastal topographies are known.The proposed project aims at bridging four substantial gaps in the state-of-the-art. Firstly, the behaviour of (i) complex and idealised model boulders and (ii) interactions between them during the tsunami runup will be analysed and compared by laboratory experiments. Investigations of the influences on boulder transport mode, path, and distance due to (iii) non-uniform bathymetric settings and (iv) sedimentary load follow afterwards. The next step comprises the development, calibration, and validation of a numerical two-phase model by using results of the physical experiments. Based on photo-technically recorded and numerically implemented data for topography and block deposits, the model shall be able to simulate tsunami-induced transport events with an unprecedented accuracy by project close-out. For the post-project future, the model application is intended for the island of Bonaire (Netherlands Antilles), where the coastal boulder sedimentology is already documented in high detail.