The 1963 Vajont Landslide: 50th Anniversary

Abstract

This editorial is intended to bring to our minds the 50th Anniversary of the Vajont Landslide occurred on 9 October 1963 at 10.39 pm in Italy, in the Dolomites of Friuli, on the borders of the Veneto Region and about 100 km north of Venice. A mass of approximately 270–300 million m of rock and debris collapsed into the reservoir generating a wave that over-topped the 261.6 m high double curved arch dam built across a V-shaped gorge (Fig. 1). The flood wave dropped into the Piave Valley destroying the town of Longarone and other villages nearby. More than 2,000 people (the real number is not known) were killed. The Vajont landslide is considered to be one of the most catastrophic slope failures and is an outstanding and valuable reference case history for the study and back analysis of the complex instability mechanisms which generally characterize deep-seated landslides and rock slopes. This dramatic event is also of particular importance for the understanding of the influence of mountainside reservoirs on the stability of the adjacent slopes, when deep-seated landslides are present which were not disclosed or fully investigated at the design stage. At the same time, interest stems from the need to find the most appropriate investigation techniques to be adopted at the design stage, including suitable numerical modelling methods to be used for the analysis of instability modes and simulation of the interaction between the rock mass and the new infrastructures to be built. Also the re-analysis of the available database on the triggering and subsequent propagation of the landslide may shed light on monitoring methods—with conventional and advanced technologies— used as key components of hazard assessment. This is of particular relevance for those countries where the need for energy and development leads to the construction of new infrastructures, including dams, of unprecedented sizes. It is noted that this editorial is only intended to remind us what is considered to be the starting point for the development of modern Rock Mechanics and Rock Engineering, when in rock as well as in soil, according to Terzaghi ‘we were over-stepping the limits of our ability to predict the consequences of our actions’ (Hoek 2007). With the intent to account for the most recent and updated studies on the Vajont landslide, the Editor has asked the help of Professor Paolo Paronuzzi from the University of Udine who, together with his research group, has been and is carrying out a comprehensive research project on different aspects and debated questions still posed on the Vajont catastrophic landslide.