ABSTRACT An integrated approach including dendrometric and dendrogeomorphological analysis, geotechnical monitoring and numerical modeling was established on a reactivating landslide in a forested Deep-Seated Gravitational Slope Deformation (DSGSD) area in Valtellina, Italy, in order to define the distribution of surface displacements in space and time as well as to identify the triggering factors (i.e. precipitation and a recent road tunneling). By means of a normalized difference eccentricity index (EI), we dated with annual resolution the surface displacements occurred over the period 1980–2016: the instability signals spread from the upper portion of the landslide (C) in 1980s to the middle section (B) especially in the 2000s, when they also occurred in the lowest portion (A). Mean Absolute EI (MAEI index) highlighted the intensity of the displacement signals, whereas changes in the MAEI series (dMAEI index) allowed to find correspondences between precipitation input and tree-ring eccentricity. A diagnostic test applied to these correspondences showed an overall accuracy of 0.74 and allowed to determine the precipitation threshold values acting as triggering factors. Topographic monitoring networks in 2016 revealed displacements <1 mm in the upper portion of the landslide, whereas the middle and lowest portion displacements were ranging 1–10 mm. The inclinometric probes confirmed the same trend for in-depth displacements, pointing out multiple sliding surfaces. A numerical stress-strain model, integrating information both from the instrumental and the dendrochronological approaches, provided information on the slope dynamics and its controlling factors, including groundwater flow conditions and the recent tunneling, thus allowing a comprehensive assessment of the geomorphological hazard.

中文翻译：

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欧洲阿尔卑斯山森林 DSGSD 地区地表坡度运动的多年代际测年：检测降水触发因素

摘要：在意大利瓦尔泰利纳（Valtellina）森林深部重力斜坡变形（DSGSD）地区重新激活的滑坡上建立了包括树木测量和树木地貌分析、岩土工程监测和数值模拟在内的综合方法，以确定空间中地表位移的分布。和时间以及确定触发因素（即降水和最近的公路隧道开挖）。通过归一化差异偏心率指数（EI），我们以年度分辨率确定了 1980 年至 2016 年期间发生的地表位移：不稳定信号从 1980 年代的滑坡上部（C）传播到中段（B ) 特别是在 2000 年代，当时它们也出现在最低部分 (A)。平均绝对 EI（MAEI 指数）突出了位移信号的强度，而 MAEI 系列（dMAEI 指数）的变化允许找到降水输入和年轮偏心率之间的对应关系。应用于这些对应关系的诊断测试显示总体准确度为 0.74，并允许确定作为触发因素的降水阈值。2016 年的地形监测网络显示，滑坡上部位移小于 1 mm，而中部和底部位移范围为 1-10 mm。倾角探头证实了深度位移的相同趋势，指出了多个滑动表面。一个数值应力-应变模型，整合了来自仪器和树木年代学方法的信息，