Landslide dams are common geomorphic phenomena, especially in high relief mountains characterized by steep slopes and narrow valleys, where even small landslides can easily block the valleys and give rise to the formation of dam lakes. Mass movements and landslide dams are among active geohazards along river valleys of the Zagros Mountains of southwestern Iran, which pose serious risks to the local inhabitants and infrastructures. This paper explores the mechanism and consequences of a typical landslide dam in 2019 in the Morzarrin Valley in Lorestan Province, Iran. Meteorological data, satellite images and Google Earth images, geology and topography maps, as well as field observations were used to evaluate the morphometric characteristics of the landslide dam. Our investigations indicate that a heavy precipitation (rain and snowfall) triggered the occurrence of the landslide in marl and limestone formations. Moreover, high steepness of the slopes and river undercutting are other controlling factors on the occurrence of landslides in this basin, as indicated by the evidence of multiple landslides along the Morzarrin Valley. The studied landslide blocked the valley and formed a dam lake with an area of 3.3 km². The landslide also destroyed and blocked the nearby road and caused damages in power lines and water transportation infrastructures and inundated fish farms. Digging a canal in the landslide dam and gradual discharge of the lake water reduced the landslide dam-break risks which particularly threatened the areas downstream.

滑坡水坝是常见的地貌现象，尤其是在以陡峭的斜坡和狭窄的山谷为特征的高起伏山脉中，即使是很小的滑坡也很容易挡住山谷并形成水坝湖。伊朗西南部Zagros山脉河谷沿岸的群众活动和滑坡坝是活跃的地质灾害，对当地居民和基础设施构成了严重威胁。本文探讨了2019年伊朗洛雷斯坦省Morzarrin谷地典型滑坡坝的机理和后果。气象数据，卫星图像和Google Earth图像，地质和地形图以及野外观察被用来评估滑坡坝的形态特征。我们的调查表明，大量的降雨（降雨和降雪）触发了泥灰岩和石灰岩地层的滑坡的发生。此外，斜坡上的陡峭度和河流底切是该盆地发生滑坡的其他控制因素，Morzarrin山谷沿岸发生了多次滑坡。研究的滑坡阻塞了山谷并形成了一个面积为3.3 km的水坝湖²。滑坡还摧毁并封锁了附近的道路，并破坏了输电线，输水基础设施和淹没的养鱼场。在滑坡坝中挖一条运河，并逐渐排泄湖水，减少了滑坡溃坝的风险，这尤其威胁到下游地区。