Table1_UAV and field survey investigation of a landslide triggered debris flow and dam formation in Eastern Carpathians.docx

In the May–August period of 2010, major heavy rains impacted the Eastern Carpathians (Northeastern Romania), leading to flash floods and triggering numerous landslides. The extreme weather conditions caused damage to the road network, extensive forest destruction, and lead to formation of impounded lakes. One of the hardest-hit areas was the mountain tributaries catchments of the Bistrița watershed. Particularly, the most significant landslide-triggered debris flow event occurred in the upper Iapa valley (Neamț County). The landslide process started near the top of the Drumul Chinezilor ridge in the Goșmanu-Geamăna Massif (Tarcău Mountains), at an elevation of 875 m a.s.l., and the flow-slide fan obstructed a 300-m section of the Iapa watercourse at 615 m a.s.l. This study compiles the climatic, anthropogenic, geological, and geomorphological evidence gathered during the field investigation in the October 2023 and utilizes Unmanned Aerial Vehicle (UAV) data collected to reconstruct the occurred debris flow-slide event. Additionally, it explores considerations regarding the reactivation of landslide processes, dam stability, and the future evolution of the impounded lake (Făgețel Lake: water surface area of 9,500 m2; maximum depth 10 m). Furthermore, the lessons learned and future actions required to prevent further mass movement associated with debris flow-slide processes in prone areas of the Eastern Carpathians are discussed.

2010年5月至8月期间，强降雨侵袭了东喀尔巴阡山脉（罗马尼亚东北部），引发山洪并诱发大量滑坡。极端气象条件对道路网络造成破坏，导致大面积森林损毁，并形成多处壅水湖泊。受灾最为严重的区域之一为比斯特里察流域（Bistrița watershed）的山地支流集水区。其中，最显著的滑坡诱发碎屑流事件发生在亚帕河谷上游（尼亚姆茨县，Neamț County）。此次滑坡过程始于塔尔考山脉戈什马努-杰马纳地块的德鲁姆·奇内济洛尔山脊顶部附近，海拔875米（a.s.l.，即海平面以上），形成的流滑扇堵塞了亚帕河道海拔615米处的300米河段。本研究整理了2023年10月野外调查期间收集的气候、人为因素、地质与地貌相关证据，并利用采集到的无人机（Unmanned Aerial Vehicle, UAV）数据对此次发生的碎屑流-滑坡事件进行重建。此外还探讨了滑坡过程复活、坝体稳定性以及该壅水湖（法盖泰尔湖，Făgețel Lake：水面面积9500平方米，最大水深10米）的未来演化态势，同时本文还讨论了东喀尔巴阡山脉地质灾害易发区内预防后续碎屑流-滑坡型块体运动所需的经验教训与未来行动方案。