Cliff Instability Areas (ASCCIE) - 2040 - 0.2m SLR

The ASCCIE_2040_02mSLR dataset is a digital dataset consisting of multiple spatial layer outputs from modelled erosion scenarios. The dataset is recommended for use at the statewide / regional scale along the Victorian coastline. Application of the data should be guided by the accompanying Victorian Coastal Cliff Assessment technical reports and expert advice. The product is not suitable for individual property scale assessments. Further information is contained in the study report "Victorian Coastal Cliff Assessment", Tonkin and Taylor, Sep 2023.Consolidated shorelines, which include soil and rock cliffs, are not able to rebuild following periods oferosion but rather are subject to a one-way process of degradation. ASCCIEs typically have two components:• Toe ErosionA gradual retreat of the cliff toe caused by weathering, marine and bio-erosion processes. Thisretreat will be affected by global process such as sea level rise and potentially increased soilmoisture. Future cliff toe position based on historical erosion rates with a factor applied toallow for the effect of future sea level rise.• Cliff InstabilityEpisodic instability events are predominately due to a change in loading or material propertiesof the cliff or yielding along a geological structure. In soft cliffs, instability causes the cliff slopeto flatten to a slope under which it is “stable” (geo-mechanically). Soil cliff slope instabilitiesare influenced by processes that erode and destabilise the cliff toe, including marineprocesses, weathering and biological erosion or change the stress within the cliff slope. Mostof the hard cliffs are stable at very steep angles. Instability events may range from small-scaleinstabilities (block or rock falls) or discontinuities, to cliff slope instability cause by large-scaleand deep-seated mass movement. The latter mode of failure in hard cliffs is rare.ASCCIE_2040_02mSLR数据集是一套包含多组侵蚀情景模型空间图层输出成果的数字化数据集。该数据集推荐应用于维多利亚州沿岸的全州/区域尺度场景。数据的使用需遵循配套的《维多利亚海岸悬崖评估》技术报告及专业建议。本产品不适用于单个地产项目尺度的评估工作。更多详细信息可参阅Tonkin和Taylor于2023年9月发布的研究报告《维多利亚海岸悬崖评估》（Victorian Coastal Cliff Assessment）。 包含土质崖壁与岩质崖壁的固结海岸线，在经历侵蚀阶段后无法自行重建，仅会发生单向退化过程。ASCCIE通常包含两个组成部分： • 崖脚侵蚀（Toe Erosion）：由风化作用、海洋侵蚀与生物侵蚀共同引发的崖脚渐进式后退。该后退过程会受到海平面上升等全球尺度过程，以及潜在增加的土壤湿度的影响。未来崖脚位置以历史侵蚀率为基础，结合用于考量未来海平面上升影响的修正系数进行测算。 • 崖壁失稳（Cliff Instability）：间歇性失稳事件主要由崖壁荷载变化、物质属性改变，或沿地质构造发生的屈服现象引发。在软质崖壁中，失稳会促使崖坡平缓至地质力学层面定义的“稳定”坡度。土质崖坡失稳受两类过程影响：一类是侵蚀并破坏崖脚的作用，包括海洋作用、风化与生物侵蚀；另一类是改变崖坡内部应力的过程。多数硬质崖壁在极陡角度下即可保持稳定。失稳事件的规模跨度较大，从小规模失稳（岩块坠落或结构断续），到大尺度深层岩体滑移引发的崖坡失稳均有涵盖。硬质崖壁的此类深层失稳模式较为罕见。