The southern part of the French Alps is studied for years in mapping and understanding of large-scale gravitational deformations. The identification and the knowledge of large-scale slope deformation (deep-seated gravitational slope deformation or DSGSD and deep-seated landslide or DSL) in the previous work of Jomard (2006) and Zerathe (2013) open a new vision of landslide processes with the reinterpretation of their dynamics and the characterization of the time scales involved. We identify DSGSD (10.109 m3) in the Var Valley associated with geological and geomorphological anomalies linked to the Messinian Salinity Crisis (MSC) and the alpine orogenesis. We use field observations, geological information (geological map, boreholes), and topographic analysis performed in a GIS environment in order to describe these anomalies. This old and partly eroded slide mass is associated with three typical DSGSD features: (1) a double-crested ridge, the Sinne Valley, (2) a large formation (2.7 × 108 m3) of slope deposit dated from the Messinian (Carros breccia), and (3) the kilometric deviation (1 to 2 km) of the Var River. We relate all these anomalies to the MSC (5.97 to 5.46 Ma) and the incision of deep canyons during this period related to this major eustatic variation (≈ 1300 m). The incision of the canyon triggered the collapse process of the DSGSD of the Sinne Valley and so destabilized the entire massif. At present, three DSLs resulting from the DSGSD deformation are still present in the area in a dormant state. Indeed, since the infilling of the Var Canyon during the Pliocene, the activity of the DSGSD has stopped.

中文翻译：

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高山深部重力斜坡变形与墨西拿盐度危机

多年来，人们一直在研究法国阿尔卑斯山南部的大尺度重力变形绘图和理解。Jomard (2006) 和 Zerathe (2013) 先前工作中对大规模斜坡变形（深层重力斜坡变形或 DSGSD 和深层滑坡或 DSL）的识别和知识开启了滑坡过程的新视野对其动态的重新解释和所涉及的时间尺度的表征。我们在与墨西拿盐度危机 (MSC) 和高山造山作用相关的地质和地貌异常相关的瓦尔河谷中发现了 DSGSD（10.109 立方米）。我们使用在 GIS 环境中进行的实地观察、地质信息（地质图、钻孔）和地形分析来描述这些异常。这个古老且部分侵蚀的滑坡体与三个典型的 DSGSD 特征有关：(1) 双顶山脊，Sinne Valley，(2) 一个大地层 (2.7 × 108 m3) 可追溯到墨西拿 (Carros breccia) 的斜坡沉积物)，以及 (3) 瓦尔河的公里偏差（1 到 2 公里）。我们将所有这些异常与 MSC（5.97 至 5.46 Ma）以及与这一主要浮海变化（≈ 1300 m）相关的这一时期深峡谷的切口联系起来。峡谷的切口引发了Sinne Valley DSGSD的坍塌过程，从而破坏了整个地块的稳定。目前，DSGSD变形产生的3条DSL仍处于休眠状态。事实上，自从上新世 Var 峡谷被填充以来，DSGSD 的活动已经停止。