Abstract Assessing initiation of rock-slope deformation and paleo-slip rates of rockslides is important to understand the impact of climate variability - in particular permafrost changes - on rockslide activity. Norway, with 6–6.5% permafrost cover today, continues to experience spatial and temporal variations in permafrost. We assess the timing of deformation initiation and potential late Pleistocene and Holocene sliding rates for six active gradually deforming rockslides in Norway using terrestrial cosmogenic nuclide dating. We evaluate the timing and rates of deformation considering a possible climate control by modelling the permafrost evolution since deglaciation for three rockslide locations: Mannen, Revdalsfjellet and Gamanjunni 3. Deformation at these sites started during or at the end of the Holocene Thermal Maximum (HTM), between 8 and 4.5 ka when permafrost in those regions was mostly degraded. At two low elevation sites, Oppstadhornet and Skjeringahaugane in western Norway, where permafrost remained absent during the Holocene, deformation started shortly after deglaciation. The timings suggest that the presence of permafrost in Norwegian rock slopes had a stabilizing effect over several millennia after deglaciation. Vertical transects of exposure ages along outcropping sliding surfaces indicate that pre-historical sliding rates seem to have decreased throughout the Holocene at all analysed rock-slope instabilities. However, modern measured sliding rates at four sites indicate a moderate to strong acceleration, compared to previous deformation rates. Three of these sites are located above or at the lower limit of alpine permafrost, where recent permafrost degradation may enhance slope destabilisation. The implication is that slope failures may become more frequent during accelerated warming in the Arctic and Subarctic.

中文翻译：

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永久冻土作为（亚）北极挪威长期岩坡变形的一级控制

摘要 评估岩石斜坡变形的开始和岩石滑坡的古滑移速率对于了解气候变率——尤其是多年冻土变化——对岩石滑坡活动的影响非常重要。挪威目前的永久冻土覆盖率为 6-6.5%，永久冻土继续经历时空变化。我们使用陆地宇宙成因核素测年评估了挪威六个活跃的逐渐变形的滑坡的变形开始时间和潜在的晚更新世和全新世滑动速率。我们通过模拟三个岩石滑坡位置自冰川消融以来的永久冻土演化来评估变形的时间和速率，考虑可能的气候控制：Mannen、Revdalsfjellet 和 Gamanjunni 3。这些位置的变形开始于全新世热最大值 (HTM) 期间或结束时，在 8 到 4 之间。5 ka 当这些地区的多年冻土大部分退化时。在挪威西部的两个低海拔地点，即 Oppstadhornet 和 Skjeringahaugane，在全新世期间仍然没有永久冻土，变形在冰川消退后不久就开始了。这些时间表明，在冰川消退后的几千年里，挪威岩石斜坡中永久冻土的存在具有稳定作用。沿着露头滑动面的暴露年龄垂直断面表明，在所有分析的岩石斜坡不稳定性下，史前滑动速率似乎在整个全新世都下降了。然而，与以前的变形率相比，现代测量的四个位置的滑动率表明有中等至强的加速度。其中三个地点位于高山永久冻土的上方或下方，最近的永久冻土退化可能会加剧斜坡的不稳定。这意味着在北极和亚北极地区加速变暖期间，斜坡崩塌可能会变得更加频繁。