A deep-seated landslide dam in the Siriu Reservoir (Curvature Carpathians, Romania)

Abstract

The Groapa Vântului (Wind’s Dip) landslide, situated in the Buzău Carpathians, on the right-hand slope of the Siriu Reservoir, occurred in April 2006, after the first local movements were signaled in September–October 2005. It represents a reactivation of an older, apparently relict (and well covered by a secular beech forest) landslide, which blocked Siriu Reservoir for several weeks and caused a major change in the sedimentation regime downstream of it. The volume of the displaced material reached almost 2.5 million m3, affecting a surface of more than 250,000 m2 and reducing the reservoir’s volume by almost 2 million m3. The landslide developed on a lithological contact of Paleogene flysch formations and features steep (40–50°) and high (up to 30 m) scarps, as well as complex inner sectors, of rotational, translational, and compresional movement. The assessment of landslide’s morphodynamic behavior is based on repeated geomorphological field mapping and measurements, differential Global Positioning System, and total station profiles, and mobile and fixed landmarks. This preliminary assessment contributes to the understanding of the behavior of old, peri-glacial landslide reactivations and also represents progress towards a better hazard assessment.