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Abstract. Surface features are produced as a result of internal deformation of active landslides, and are continuously created and destroyed by the movement. Observation of their presence and distribution, and surveying of their evolution may provide insights for the zonation of the mass movement in sectors characterized by different behaviour. The present study analyses and describes some example of surface features observed on an active mass movement, the Slumgullion earthflow, in the San Juan Mountains of southwestern Colorado. The Slumgullion earthflow is one of the most famous and spectacular landslides in the world; it consists of a younger, active part which moves on and over an older, much larger, inactive part. Total length of the earthflow is 6.8 km, with an estimated volume of 170 × 10 6 m 3 . Its nearly constant rate of movement (ranging from about 2 m per year at the head, to a maximum of 6-7 m per year at its narrow and central part, to values between 1.3 and 2 m per year at the active toe), and the geological properties of moving material, are well suited for the observation of the development and evolution of surface features.In the last 11 years, repeated surveying at the Slumgullion site has been performed through recognition of surface features, measurements of their main characteristics, and detailed mapping. In this study, two sectors of the Slumgullion earthflow are analysed through comparison of the features observed in this time span, and evaluation of the changes occurred: they are the active toe and an area located at the left flank of the landslide. Choice of the sectors was dictated in the first case, by particular activity of movement and the nearby presence of elements at risk (highway located only 250 m downhill from the toe); and in the second case, by the presence of many surface features, mostly consisting of several generations of flank ridges.The active toe of the landslide is characterized by continuous movement which determines frequent variations in the presence and distribution of surface features, as evidenced by the multi-year observations there performed. In addiCorrespondence to: M. Parise (cerimp06@area.ba.cnr.it) tion, monitoring of the inactive material just ahead of the active toe showed that this sector is experiencing deformation caused by the advancing toe. Mapping and interpretation of the different generations of flank ridges at the narrowest and central part of the active Slumgullion landslide evidenced, on the other hand, the gradual narrowing of the mass movement, which was accompanied by a reduction in the thickness of the material involved in landsliding.Multi-time observation of the surface features at the Slumgullion earthflow allowed to reconstruct the evolution of specific sectors of the mass movement. This low-cost approach, whose only requirements are the availability of a detailed topographic map, and repeated surveying, is therefore particularly useful to better understand the kinematics of active mass movements, also in order to design the more a...

Izvleček UDK 502.6:551.44(450.75) Fabiana Calò & Mario Parise: Ocenjevanje sprememb kraškega okolja zaradi vpliva človeka v južni Italiji Kraško okolje je izredno občutljivo za uničevanje in onesnaževanje. čeprav je »nosilna sposobnost« tega naravnega okolja majhna, so na krasu najrazličnejše človeške dejavnosti, ki vplivajo na njegovo površje in podzemlje. Da bi ocenili stopnjo takih sprememb na značilnem kraškem ozemlju v Sredozemlju, je bilo izbranih dvoje področij v Apuliji (jugovzhodna Italija). Posledice, ki jih je povzročil človek, so bile ugotovljene s pomočjo pred kratkim razvitega »indeksa sprememb na krasu«, ki upošteva fizične, biološke in družbene vidike, obenem pa so bili za vsako skupino ovrednoteni številni pokazatelji. Ti so bili točkovani in tako sta bili ovrednoteni intenzivnost in obseg človekovega vpliva na kraško okolje. Poznavanje obravnavanega ozemlja temelji tako na neposrednem opazovanju kot na terenskih preučevanjih ter na kritičnem ovrednotenju podatkov iz strokovnih člankov in poročil lokalnih združenj. Ker gre za celostno in vsestransko metodo, so upoštevane različne znanstvene panoge in zakonodaja. Tako dobljeni izsledki za preučevana ozemlja kažejo na nujnost sonaravnega urejanja človeških dejavnosti, kot sta npr. lomljenje in čiščenje kamenja, oboje je na široko razširjeno in ki predstavljata najbolj nevarno dejavnost za kraške površinske in podzemeljske oblike v Apuliji. Ti dejavnosti močno spreminjata prvotno kraško površje in povzročata delno ali celotno uničenje podzemeljskih jam. Ta študija predstavlja predhodno oceno sprememb na krasu v Apuliji in bi morala biti vključena v bodoče raziskave drugih ozemelj te regije, da bi lahko bolje razumeli prednosti te metode in njeno uporabnost za različna kraška okolja. ključne besede: spremembe na krasu, vpliv človeka, indeks sprememb na krasu, Apulija, Italija.

The peculiarities of karst environment make it highly vulnerable to a number of geohazards: As concerns the natural hazards, the main categories are sinkholes, slope movements, and floods. To these, anthropogenic hazards have to be added, as pollution events, land use changes resulting in loss of karst landscape, destruction of karst landforms, etc. Even carrying out engineering works without taking into the due consideration, the peculiar aspects of karst can be extremely dangerous and cause risk to the natural environment, as well as to the man-made infrastructures and buildings. In the second half of last century, man has definitely become one of the most powerful factors that can cause changes in the karst environment, produce direct damage, predispose the territory to threatening events, and increase with mismanagement actions the negative effects deriving from natural hazards. In this chapter, the main hazards in karst are briefly described with particular focus on the natural hazards and with the help of some case studies

Fetida Cave is an active sulfuric acid cave influenced by seawater, showing abundant microbial communities that organize themselves under three main different morphologies: water filaments, vermiculations and moonmilk deposits. These biofilms/deposits have different cave distribution, pH, macro- and microelement and mineralogical composition, carbon and nitrogen content. In particular, water filaments and vermiculations had circumneutral and slightly acidic pH, respectively, both had abundant organic carbon and high microbial diversity. They were rich in macro- and microelements, deriving from mineral dissolution, and, in the case of water filaments, from seawater composition. Vermiculations had different color, partly associated with their mineralogy, and unusual minerals probably due to trapping capacities. Moonmilk was composed of gypsum, poor in organic matter, had an extremely low pH (0–1) and low microbial diversity. Based on 16S rRNA gene analysis, the microbial composition of the biofilms/deposits included autotrophic taxa associated with sulfur and nitrogen cycles and biomineralization processes. In particular, water filaments communities were characterized by bacterial taxa involved in sulfur oxidation and reduction in aquatic, aphotic, microaerophilic/anoxic environments (Campylobacterales, Thiotrichales, Arenicellales, Desulfobacterales, Desulforomonadales) and in chemolithotrophy in marine habitats (Oceanospirillales, Chromatiales). Their biodiversity was linked to the morphology of the water filaments and their collection site. Microbial communities within vermiculations were partly related to their color and showed high abundance of unclassified Betaproteobacteria and sulfur-oxidizing Hydrogenophilales (including Sulfuriferula ), and Acidiferrobacterales (including Sulfurifustis ), sulfur-reducing Desulfurellales, and ammonia-oxidizing Planctomycetes and Nitrospirae. The microbial community associated with gypsum moonmilk showed the strong dominance (>60%) of the archaeal genus Thermoplasma and lower abundance of chemolithotrophic Acidithiobacillus , metal-oxidizing Metallibacterium , Sulfobacillus , and Acidibacillus . This study describes the geomicrobiology of water filaments, vermiculations and gypsum moonmilk from Fetida Cave, providing insights into the microbial taxa that characterize each morphology and contribute to biogeochemical cycles and speleogenesis of this peculiar seawater-influenced sulfuric acid cave.