Paola Fredi

Morphological and morphometric approach to the study of the structural arrangement of northeastern Abruzzo (central Italy)

Abstract The morphotectonic research at the Dipartimento di Scienze della Terra of the Universita di Roma “La Sapienza” aims to define the role of tectonics and neotectonics in the morphological evolution of central Italy. In this context the relationships between morphology and tectonics have been investigated in an area of northern Abruzzo extending from the Apennine chain to the Adriatic Sea. Morphological and morphometric analyses carried out show that the geomorphological evolution of the study area was strongly affected by tectonics, especially recently. The most recent extensional tectonics intersect the previous compressive structures (overthrust, reverse faults, folds, strike-slip faults) determining the structural arrangement characterized by uplifted and downthrown blocks. Morphological analysis shows that extentional tectonics occurred with the following alignments: NW-SE, NNW-SSE, NE-SW, ENE-WSW, N-S and E-W. The spatial variability of amplitude of relief values corroborated the observations obtained from previous analyses; in particular the existence of different blocks, differentially uplifted along the alignments mentioned above. Finally, data obtained through the statistical analysis of preferred stream orientations confirm the previous considerations, showing that the same tectonic directions markedly influenced the drainage network development. Streams of lower order preferentially follow the N-S and E-W directions which suggests that these tectonic trends were active until very recent times (at least up to the Late Pleistocene). The results obtained testify both to the effectiveness of the methodological approach and the likelihood of the proposed morphotectonic arrangement of the study area.

Morphological and geochemical evidence of neotectonics in the volcanic area of Monti Vulsini (Latium, Italy)

Interdisciplinary research has been carried out to contribute to the definition of the neotectonic arrangement of the eastern area of Monti Vulsini, affected by Upper Pleistocene volcanic activity. Particularly, geochemical and geomorphological inquiries have been performed to identify tectonic elements whose recent activity could be related to the volcanic history of this area. The morphological field evidence of tectonics, as well as the analysis of azimuthal distribution of stream channels and the statistical analysis of the amplitude of relief (Ar), revealed the eastern Monti Vulsini volcanic area to be controlled by different tectonic alignments. At the same time the geochemical contribution, focused on geostatistical elaboration of soil–gas data, has attempted to process unbiased criteria to define soil–gas anomalies and to infer correlation with their fault-related linear geometry. In particular, rose diagrams of anomalous gas concentration alignments and azimuthal distribution of stream channels, performed for each hierarchical order, were compared to obtain information about the location and orientation of tectonic elements, as well as about the possible reconstruction of their activity in recent times, by means of relative chronology.

The Aeterna Urbs Geomorphological Heritage (Rome, Italy)

The largest European cities are characterised by millennia of urbanisation. ‘Man-made layering’ over time has modified the original natural setting on which these cities have developed, but an expert eye can often still recognise the ancient geomorphological features of the landscape. We show an example of the identification of the original geomorphological characteristics of the landscape over which the city centre of Rome developed, by means of a geomorphological survey conducted in this urban environment. The aim of the analysis is the enhancement of geotourism in the city centre, by describing the palaeogeography of ancient Rome through the landforms that are still visible. The geomorphological survey led to the identification of two geomorphosites. We developed an evaluation model of the Geotourist Value of a Site (VSG index), which consists of the quantification of five fundamental attributes for a geosite, characterizing its scientific and geotourist interests. The VSG index produces an order of priority for geosites for their enhancement. These results are transferred to the proposal for a geotourist itinerary, along which the selected geosites are joined and related to the historical and cultural features of the city. The itinerary is also represented on a geotourist map, created through the union of scientific and popularised electronic devices. The major outcome of this study is to supplement a proposal for the developing the historical and cultural tourism of the Aeterna Urbs combined with its natural environment features, highlighting the importance of the close connection between these themes.

Contribution for an Urban Geomorphoheritage Assessment Method: Proposal from Three Geomorphosites in Rome (Italy)

Abstract Urban geomorphology has important implications in spatial planning of human activities, and it also has a geotouristic potential due to the relationship between cultural and geomorphological heritage. Despite the introduction of the term Anthropocene to describe the deep influence that human activities have had in recent times on Earth evolution, urban geomorphological heritage studies are relatively rare and limited and urban geotourism development is recent. The analysis of the complex urban landscape often need the integration of multidisciplinary data. This study aims to propose the first urban geomorphoheritage assessment method, which originates after long-lasting previous geomorphological and geotouristic studies on Rome city centre, it depict rare examples of the geomorphological mapping of a metropolis and, at the same time, of an inventory of urban geomorphosites. The proposal is applied to geomorphosites in the Esquilino neighbourhood of Rome, whose analysis confirm the need for an ad hoc method for assessing urban geomorphosites, as already highlighted in the most recent literature on the topic. The urban geomorphoheritage assessment method is based on: (i) the urban geomorphological analysis by means of multitemporal and multidisciplinary data; (ii) the geomorphosite inventory; and (iii) the geomorphoheritage assessment and enhancement. One challenge is to assess invisible geomorphosites that are widespread in urban context. To this aim, we reworked the attributes describing the Value of a site for Geotourism in order to build up a specific methodology for the analysis of the urban geomorphological heritage.

Multi-method Evaluation of Denudation Rates in Small Mediterranean Catchments

The paper presents the results of the research tasks of the Quantitative Geomorphology Working Group (of the Italian Association of Physical Geography and Geomorphology) focused on multi-method evaluation of denudation rates in small catchments of Italy. Several study areas are compared with the goal of quantifying the morphodynamic evolution in different response times and with traditional and innovative techniques. The final aims are the direct erosion monitoring, the geomorphic analysis for the comprehension of drainage basin morphodynamics, up to the geomorphological hazard evaluation. The catchments are key Mediterranean areas particularly sensitive to climatic and anthropic modifications. The efforts of the Working Group are finalized to favour scientific collaboration activities among members with the aim of strengthen the potential of Quantitative Gomorphology in morphodynamic studies.

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

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.

Morphological Regions of Italy

This chapter presents a synthesis of the wide variety of landscapes that makes Italy a very interesting country from a geomorphological point of view. The complex and lively geological history, responsible for the peculiar tectonic arrangement of Italy, the high heterogeneity of outcropping rocks and the distinct distribution of altitudes, together with the different types of climates are the main causes of the landscape varieties. The main natural aspects of the “Morphological Regions” of Italy are described; that is to say those areas of the Italian territory marked by a dominant type of landscape—even though often strongly diversified within themselves—which resulted from both the conditioning of the geological structure and the predominance of given exogenous processes, in relation to climatic conditions.

A Route of Fire in Central Italy: The Latium Ancient Volcanoes

In the western portion of Latium (Central Italy) a series of ancient, generally evident volcanic edifices and numerous lakes hosted in depressions is present. They are directly or indirectly tied to severe volcanism which occurred between 2 and 0.08 Ma ago. From a geomorphological point of view, it is possible to identify different volcanic landscapes, whose appearance mainly depends on the magma chemistry. The landscape of the Tuscan-Latium Magmatic Province, which was fed by silicic magmas, is typified by numerous lava domes, rising up from a generally flat ignimbritic plateaux. The landscape of the alkaline potassic volcanism shows strong differences that are tied to the existence or not of well-identified central volcanic edifices. In the first case the landscape is dominated by the presence of outstanding volcanic relief; in the second one many different minor emission centres are scattered over large flat areas, mainly built up by pyroclastic flows.

Recent Tectonics in the Origin and Evolution of Gran Bajo del Gualicho, Argentina

The results of an interdisciplinary research program on the Gran Bajo del Gualicho (Rio Negro, Argentina) are reported. Geological, morphological, gravimetric, and geochemical studies provide the basis for a reconstruction of the possible origin and evolution of this endorheic depression. On the basis of the available data, the hypothesis is advanced that the depression had a tectonic origin (according to NNW-SSE and ENE-WSW tectonic lines) and subsequently was shaped by exogenous forces that obscured the original fault scarps and caused the depression to assume its present characteristics.