Francesco Troiani

Rockfall runout, Mount Cimone area, Emilia-Romagna Region, Italy

Numerous mass movements of different typology characterize both mountainous and piedmont sectors of the Emilia-Romagna Region (Apennine chain, North Italy). Although a less spatially frequent landslide typology within the region, rock falls represent severe threats to buildings, roads and persons due to their high propagation velocity. This paper presents an extract of the Emilia-Romagna regional map of the rock fall runout areas at a scale of 1:25,000. The analysis of rock fall runout areas was based upon a three-dimensional morphological method (TDM). The zone presented in the Main Map encompasses the area surrounding Mount Cimone, in the Emilia-Romagna Region. The proposed regional map of rockfall runout is noteworthy for planning actions and strategies aimed at the prevention and reduction of landslide risk at a regional scale.

Stream Length-Gradient Index Mapping as a Tool for Landslides Identification

The Stream Length-Gradient (SL) index is used to detect knickpoints potentially related to surface and sub-surface deformation processes. In this work, the SL index has been calculated along streams draining the southern sector of the Emilia-Romagna Region within the Northern Apennines (Italy), to detect knickpoints associated with active landslides. The methodology allowed the rapid analysis of an area of ca. 2300 km\(^{2}\). Approximately thirty hillslopes potentially affected by landslides were identified studying the SL index outlier values. Field survey confirmed the presence of large deep-seated landslides associated with 90 % of the observed anomalies. This study illustrates that stream profiles metrics may have a high potential in different geological studies covering wide areas in a short time and investing limited resources.

Historical geospatial database for landslide analysis: the Catalogue of Landslide OCcurrences in the Emilia-Romagna Region (CLOCkER)

A review of the content, structure, accuracy, and completeness of the Catalogue of Landslide OCcurrences in the Emilia-Romagna Region (CLOCkER) is presented. CLOCkER is a historical database, designed and developed for all types of landslides in the hilly-mountain area of the Emilia-Romagna section of the Northern Italian Apennines. Historical data have been gathered through a collection of numerous sources, including technical reports, historical archives, scientific literature, and newspapers. The information obtained, which has been evaluated to assess its temporal precision and spatial accuracy, has been recorded in a catalogue consisting of a Database Management System (DBMS) linked to a geographical information system (GIS) interface. The catalogue presently includes 14,416 records of documented landslide occurrences, dating from Middle Ages up to the present. The catalogue is associated with a landslide inventory, continuously updated by the Geological Survey of the Emilia-Romagna Region, where information on the shape, typology, and state of activity of more than 80,000 landslides is included. Our assessment of catalogue quality reveals a satisfactory spatial accuracy and a level of completeness comparable with the theoretical target proposed in the literature for complete inventories. Outputs indicate that CLOCkER can be a reference example useful for other regional historical landslide catalogues. Such reference datasets are useful for a wide range of landslide assessment purposes and can provide practical assistance for stakeholders involved in both scientific and technical fields, forming the basis for landslide temporal trend reconstruction that is essential for landslide hazard evaluation at different spatial-temporal scales. CLOCkER is open access, freely available online.

Testing geomorphic signal of active normal faulting: The case of the Cittanova Fault (Calabria, southern Italy): Testing geomorphic signal of active normal faulting (Cittanova Fault)

Extracting tectonic signals from the landscape is an important challenge for constraining the style and rate of deformation associated with active faults, especially where their displacement history cannot be independently determined. Based on previous paleoseismological data coupled with new geomorphological field work and C dating of geomorphic markers, we analysed the geomorphic signal of the along-strike differential throw of the Cittanova Fault in southern Calabria (Italy), the recent activity of which is already well documented and constrained. Through DTM-derived stream power law parameters (SL and χ), we provide evidence of drainage network disequilibrium and reorganization in response to fault growth and deformation style. Furthermore, a methodological test of the reliability of the χmetric as a proxy for the differential throw along the strike of active normal faults provided good preliminary results, consistent with a strong inverse linear correlation with fault throw. Copyright

Geomorphological map of the Montelago area (North Marche Apennines, central Italy): constrains for two relict lakes

The hamlet of Montelago (‘Mountain of the Lake’) lies within the northern Marche Apennines close to the watershed of Fosso del Lago (‘Stream of the Lake’): both Italian toponyms clearly suggest the presence of a paleolake. Official geological maps reported lacustrine sediments within the upper basin of the Fosso del Lago stream, where outcrops of lacustrine sediments have also been noted for about five decades. The nineteenth-century Gregorian cadastral map also reports water ponds roughly in the area where lacustrine sediments were found: nonetheless, their position is clearly shifted upstream with respect to the reported lacustrine sediments. In this context, we have recently performed a targeted geomorphological survey addressed at unravelling such apparent discrepancy. Our study confirms the occurrence of lacustrine sediments spanning from Atlantic up to Sub-Boreal exactly in the place reported by previous geological works. The detailed geomorphological map created for the area allowed us to adequately locate previously published subsurface prospecting both highlighting landslide damming as the process responsible for lake formation and providing information for an adequate morphoevolutive reconstruction of the area. Geomorphological mapping also resolved the problem of the different position of the ponds mapped by the Gregorian Cadastre, stating that these had no direct relationships with the former lake but rather consisted of a small man-made reservoir directly connected by broad channels to springs which are currently dried-out.

The Role of Lithology

Abstract Badlands can develop on bedrock and/or weathered material, the characteristics of which play a key role on hillslope processes in a range of climate conditions. Therefore, fundamental attention should be given to badland materials, the main features of which are grain size, clay mineralogy and physico-chemical characteristics. The typical weathering profile consists of crust, subsurface and unweathered material, but depending on climatic, lithological, topographic and hydrological factors, the properties and appearance of both surface and subsurface materials change over time. Through time, regolith formed on erodible and dispersive bedrock materials tends to stabilize, again as a function of slope and climate conditions because prolonged precipitation can cause decrease in surface strength and runoff and reduce the dispersivity of the surface. Vegetation also has distinct role in stabilizing the clayey sediments due to lowering the dispersivity in the upper horizon of the badland material, even though such stabilization is often not permanent and erosion processes can sometimes reoccur. Finally, all the above cited factors and properties of badland materials play a complex and key role in the development of different geomorphic processes and related landforms.

The use of the slope-area function to analyse process domains in complex badland landscapes: Process domains in complex badland landscape

This paper explores the effectiveness of the widely-used functional relationship between drainage area (A in m) and slope (S in m/m) to identify local process domains and aid interpretation of process interactions in a complex badland landscape. In order to perform this investigation, a series of sub-basins tributary to the Formone River in the Orcia catchment (central Italy) were selected as a suitable study area within which to explore our questions, given these basins’ general representativeness of local terrain, the availability of a high resolution digital terrain model and previous extensive geomorphological research. Eroding basins containing both calanchi and landslides are common in the sub-humid badland landscape of central Italy, where field observation identifies a complex pattern of erosive processes associated with a history of uplift, despite which parts of the local landscape appear disconnected. Results reveal that the shape of all S–A curves (plotted using S data binned on log A) is comparable with that described in the literature, although sub-basins containing calanchi generally plot with higher S values than non-calanchi ones, except in the ‘fluvial’ section of the plots. Second, when viewed on total data (non-binned) S–A plots, landslide source area domains and calanchi domains are entirely coincident in all basins, supporting a cause–effect relationship. Additional plotting of the frequency characteristics of the raw data in a new way supports the interpretation that calanchi frequently initiate in landslide scars. In general though, although the S–A plots can contribute to the disentanglement of geomorphological behaviour in some complex erosional landscapes, it became apparent that in this landscape, process domains do not separate out with clarity along the A axis as suggested by theory. Despite this, an alternative, broader-scale morphoevolutive model can be proposed for the development of within-landslide calanchi, driven by changes to basin connectivity to the base channel.

Rocky Cliffs Joining Velvet Beaches: The Northern Marche Coast

The northern Marche coastal area epitomizes many of the elements forming the rich natural, historical and cultural tissue of the Adriatic seaside of central Italy. The natural heritage, partly protected in natural reserves, also amalgamates with tourist facilities that exploit several renowned beach resorts. The northern Marche coastal area, consisting of a coastal plain interposed between two rocky shore sectors, forms a peculiar blend of different geomorphological units with distinctive landforms. The coastal plain joins landwards fossil cliffs and includes the major river mouths. The rapidly recessing rocky shores develop structural landforms, sea-stacks and benches. Both active and relict cliff retreat induces extensive landsliding in the whole sea-facing hillslopes.

Remote sensing investigation techniques for the analysis of rocky slope stability in remote areas: a test from the Sierra Madre Occidental, Mexico

Direct field survey to assess slope stability in steep and remote rocky cliffs is time demanding and highly consuming in term of human and economic resources. However, evolving technologies allow remotely sensed data integrated with GIS to theoretically provide equivalent information. Here we present a case study comparison of these methods applied to the Eastern valley-side of the Chinipas River, Sierra Madre Occidental, Mexico. Results show that remote sensing procedures provides the same discontinuity sets and equivalent attitude information with respect to the data acquired during field survey.