Abstract
The "Vajont disaster" of 9 October 1963, a paradigm of the catastrophe of human origin, is illustrated through the exceptional photos taken by Edoardo Semenza before and immediately after the event, presented in a new English exhibition. Edoardo Semenza was a geologist and one of the Italian leading landslide researchers. He put his distinctive mark on the understanding of the Alps, making original contributions to the geology, tectonics and geomorphology of the Dolomites. Semenza was the geologist who discovered that an ancient landslide mass was present on the southern side of the Vajont valley upstream from the reservoir under construction, before the first movements occurred on the slope. In the images shown in the thirteen roll-ups that make up the exhibition (Fig. 1), the intuitions, growing awareness, and sense of urgency of the man who first recognized the existence of the ancient landslide become evident. They reveal his " mente et malleo " ("with the mind and the hammer") approach, which allowed him to develop a model of the slope and what today we call risk scenarios. His discovery was immediately taken into consideration by the designer and project managers of the dam, albeit only as a hypothesis to be verified with follow-up research and investigations. Unfortunately, his work, which lasted until 1961, did not prevent the disaster from taking place. The hundreds of photos of the landslide and of the valley taken by Semenza between 1959 and 1963, allow us to access both his intimate and personal, and professional dimensions. A part of these materials, taken from the volume and CD "The photos of the Vajont landslide" and from Edoardo Semenza's book on the landslide, is shown in the roll -up banners, and constitutes a contribution to the discussion. Texts, images and captions are selected and adapted from these two publications. Through this exhibition and a renewed attention to Semenza's work we hope to raise awareness on the fundamental role that the knowledge of geology holds for the respect and protection of the environment. The first version of the exhibition " La storia del Vaiont: la conoscenza della frana attraverso le foto di Edoardo Semenza " was organized by AIGA and the National Council of Geologists (CNG) on the occasion of the fiftieth anniversary of the landslide (GENEvOIs & PREsTININZI, 2013). It was hosted by over 30 university campuses, several high schools, research centers, and museums. Launched in Naples during the National Conference of Young Researchers in Engineering Geology in February 2013, it continued its journey throughout Italy. By the end of 2014, it had been visited by several thousand students. Surrounding it, the departments or museums that hosted it organized significant events of a educational/scientific nature. It contributed to the spread of geological culture in general. It also received extensive coverage in national and local media and newspapers. In 2023, a renewed graphical version of the exhibition, in English, was realized by the Italian Association of Engineering and Environmental Geology (AIGA - Associazione Italiana di Geologia Applicata e Ambientale) and presented to the public on the occasion of the 6th World Landslide Forum in Florence for the sixtieth anniversary of the Vajont disaster. The landslide is still today the subject of debate and scientific reflection, due to the extraordinary amount of data available, as well as to the corpus of memories, stories, and testimonies that affected communities preserve and continue to build.
Semenza repeatedly stressed the need to collect field data to understand slope failure conditions as a basis of correct landslide modelling. He strongly believed both in the role of geology and geomorphology as fundamental support to any engineering project and in the importance of a good communication between the various specialists working on large projects. In these aspects, just like in his research work, he was a pioneer and a leader for the whole geological community.