Moving Geosites: How Landslides Can Become Focal Points in Geoparks

Latest Trends in Engineering Mechanics, Structures, Engineering Geology Moving geosites: how landslides can become focal points in Geoparks DOMENICO CALCATERRA1*, DOMENICO GUIDA2 , PAOLO BUDETTA3, PANTALEONE DE VITA1, DIEGO DI MARTIRE1 AND ANIELLO ALOIA4 1. Department of Earth Sciences, Environment and Resources, Federico II Naples University, Italy Corresponding author: [email protected] 2. Department of Civil Engineering, Salerno University, Italy 3. Department of Civil, Arch. and Env. Engineering, Federico II Naples University , Italy 4. National Park of Cilento, Vallo Diano and Alburni - Geopark, Italy Abstract: - Landslides are both landforms and geomorphic processes contributing to the long-term landscape evolution and one of the deadliest sources of natural hazard which endanger lives, property and activities. Many people in the world have experienced historical coexistence with landslides and related hazard, adapting settlement location and typology, land use and best practices. At large, local cultural identity is strongly influenced by this adaptation, while, in a few cases, landslides are expressions of both geodiversity and cultural identity. In these cases, it seems appropriate to refer to “moving geosites”, where academic researches supported by geoparks provide insights to educational system and dissemination to the public administrations, both as geodiversity functioning and effective approach to landslide risk reduction by raising public awareness. Key-Words: Landslide, Geosite, Moving Geosite, Geodiversity, European Geopark Network, Cilento-Vallo di Diano-Alburni Geopark The territory of Cilento and Vallo di Diano Geopark 1 Introduction A recent study carried out by ISPRA, the Italian originally fell under the jurisdiction of two RBAs Agency for Environmental Protection and Research (RBA Interregionale del Fiume Sele and RBA (IFFI Project - Italian Landslide Inventory; [1]) Regionale “Sinistra Sele”), which in 2012 have inventories more than 485.000 landslides in Italy, been unified, along with a third RBA, under a new distributed over all the twenty Italian regions. RBA named “Autorità di Bacino regionale Among them, Campania region occupies a quite Campania Sud ed Interregionale per il bacino high position in this unenviable ranking, as regards idrografico del fiume Sele”. Both RBAs have landslide density, with 171 events/100 km2. In Italy, recently updated their HSPs; integrating the landslide risk and its mitigation have been respective landslide-inventory maps, Figure 1 has organically treated for the first time with the Law been created. Here, slightly less than 13.500 no. 183/1989. However, it was only after the huge landslides are represented, many of which never tragedy occurred at Sarno and in other four inventoried beforehand [2]. Campanian towns (160 death due fast-moving The Geopark’s landslides pertain to all the possible landslides) on May 5, 1998 that the above Law was types recognized by modern classification schemes. fully accomplished, especially as regards to the According to the Cruden & Varnes’ landslide implementation of the River Basin Authorities classification [3], rotational and translational slides (RBAs), public bodies responsible for the are the most common phenomena, followed by governance of the hydrographic basins. RBAs, complex movements; the latter, in turn, represent the widest ones, in terms of areal extent. Landslides among their duties, have to carry out the “Basin 2 Plan”, a comprehensive programme of land cover about 300 km of the Geopark territory and management projects, which include the Hydro- are present in 78 out of the 82 municipalities geomorphological Setting Plan (HSP) aimed at belonging to the Geopark community. Laurino, identifying areas exposed to landslide and flood Centola and Celle di Bulgheria are the municipalities where landslides affect more than 10 risk, and at mitigating it within levels consistent 2 with the existing land use, so as to safeguard human km of territory. Most of the inventoried landslides lives and reduce as much as possible the damage to show an average intensity, which can be expressed material properties. as a maximum expected velocity from slow to ISBN: 978-960-474-376-6 162 Latest Trends in Engineering Mechanics, Structures, Engineering Geology moderate (from 5 × 10-5 to 5 × 10-1 mm/s). different geo-materials). This is the main reason Consequently, according to the existing Italian laws why, as regards landslides, typological and regulations, the Geopark territory is prevailingly classifications, which subdivide phenomena into affected by average landslide risk. repeating patterns (“types”) characterized by some During the 12th EGN 2013 Conference, organized descriptors, got success with time. According to by the Cilento, Vallo Diano and Alburni Geopark [9], any landslide can be classified and described by (CVDA Geopark), the following topic was two nouns: the first describes the material and the discussed: “Geoparks, as innovative approaches to second describes the type of movement (e.g. rock raise public awareness in natural geo-hazards, fall, debris flow). Additional aspects of a landslide climate change and sustainable use of the need to be defined, especially when its hazard is resources”. In this context, according to the mission considered. It is therefore convenient to indicate for on “raising public awareness” about landslide a given landslide its “magnitude” or “intensity”, as hazard and risk, the aim of the CVDA Geopark is to “a set of spatially distributed parameters describing convert some representative landslide areas into the destructiveness of a landslide”[10]. Despite publicly accessible geosites. This action was such a straightforward definition, a univocal considered as an effective way to strengthen general quantitative definition of “landslide intensity” is not awareness and knowledge of all the possible available at present, since it can be quantitatively relevant geological assets, singular assessed only using a variety of parameters, such as geomorphological evolution and historical aspected or actual maximum velocity, total cohabitation experience about landslides [4]. displacement, volume of the involved mass, depth Previous studies have addressed many efforts to of the moving mass, etc.. Some of the above assess landslide risk affecting geosites for parameters, however, represent key-factors in the geotourism accessibility (e.g. [5]), while minor landslide hazard evaluation. Among them, the attention was given in the literature as to consider a movement velocity is unanimously considered as an landslide as a geosite in itself (e.g. [6]). element which can be easily linked to human This paper discusses on conceptual premises, response, since the destructive potential of a scientific definitions and institutional formalization landslide depends on its velocity [9] and [10]. of a new concept in geodiversity management: Landslides from extremely rapid to very rapid, “moving geosite”. As to make the concept more exhibiting velocities of the order of 5 m/s, are perceptible, a few cases of “moving geosites” are relevant in terms of danger to human life because described. corresponds to the speed of a person running and could be called “catastrophic velocity”. Slower movements (slow, very slow, extremely slow) usually cause only material damage, being 2 From Landslide to Moving Geosite characterized by rate of movements lower than 5 × The concept of landslide was effectively stated by 10-3 mm/s. In these cases, living with landslides is Varnes [7] as “a downward and outward movement possible, especially when the phenomena are under of slope forming materials composed of natural control, by means of monitoring instruments (e.g.: rock, soils, artificial fills, or combinations of these inclinometers, piezometers, GPS, remote sensing). materials”. The same author simplified its previous Many landslides show an intermittent behaviour definition, by reducing it to “a downward and during their long-term evolution, following the first- outward movement of slope forming materials under time activation. Long periods of very slow bulk the influence of gravity”. Cruden [8] further deformations are interrupted by relatively short simplified such definition, stating that a landslide term, fast, partial or global re-activations. Return denotes “the movement of a mass of rock, debris or times of these re-activations can be very variable, earth down a slope” from decadal to centennial or even millennial. When As it occurs whenever a complex issue must be reactivations span from decadal to centennial, simplified, to classify landslides has been one of the historical memory promotes the human cohabitation main interests for researchers and professionals. and coexistence with landslides. On the contrary, in Due to their intrinsic complexity, landslides cannot case of very long return times, people could not rely be easily classified following a rigid taxonomic on experience and tend to forget the past dangerous system, as in the case of plants or animals, due to phenomena and the previously affected areas. In this several difficulties (e.g. events not perfectly case, it may be appropriate to associate usual repeatable; occurrence of different causes, monitoring activities with communication and movements and morphology; involvement of public awareness focused on the most representative ISBN: 978-960-474-376-6 163 Latest Trends in Engineering Mechanics, Structures, Engineering Geology examples of reactivable

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